fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "tree-log.h"
  20 #include "disk-io.h"
  21 #include "print-tree.h"
  22 #include "volumes.h"
  23 #include "raid56.h"
  24 #include "locking.h"
  25 #include "free-space-cache.h"
  26 #include "free-space-tree.h"
  27 #include "math.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31
  32 #undef SCRAMBLE_DELAYED_REFS
  33
  34 /*
  35  * control flags for do_chunk_alloc's force field
  36  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  37  * if we really need one.
  38  *
  39  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  40  * if we have very few chunks already allocated.  This is
  41  * used as part of the clustering code to help make sure
  42  * we have a good pool of storage to cluster in, without
  43  * filling the FS with empty chunks
  44  *
  45  * CHUNK_ALLOC_FORCE means it must try to allocate one
  46  *
  47  */
  48 enum {
  49         CHUNK_ALLOC_NO_FORCE = 0,
  50         CHUNK_ALLOC_LIMITED = 1,
  51         CHUNK_ALLOC_FORCE = 2,
  52 };
  53
  54 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  55                                struct btrfs_fs_info *fs_info,
  56                                 struct btrfs_delayed_ref_node *node, u64 parent,
  57                                 u64 root_objectid, u64 owner_objectid,
  58                                 u64 owner_offset, int refs_to_drop,
  59                                 struct btrfs_delayed_extent_op *extra_op);
  60 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  61                                     struct extent_buffer *leaf,
  62                                     struct btrfs_extent_item *ei);
  63 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  64                                       struct btrfs_fs_info *fs_info,
  65                                       u64 parent, u64 root_objectid,
  66                                       u64 flags, u64 owner, u64 offset,
  67                                       struct btrfs_key *ins, int ref_mod);
  68 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  69                                      struct btrfs_fs_info *fs_info,
  70                                      u64 parent, u64 root_objectid,
  71                                      u64 flags, struct btrfs_disk_key *key,
  72                                      int level, struct btrfs_key *ins);
  73 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  74                           struct btrfs_fs_info *fs_info, u64 flags,
  75                           int force);
  76 static int find_next_key(struct btrfs_path *path, int level,
  77                          struct btrfs_key *key);
  78 static void dump_space_info(struct btrfs_fs_info *fs_info,
  79                             struct btrfs_space_info *info, u64 bytes,
  80                             int dump_block_groups);
  81 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  82                                u64 num_bytes);
  83 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
  84                                      struct btrfs_space_info *space_info,
  85                                      u64 num_bytes);
  86 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
  87                                      struct btrfs_space_info *space_info,
  88                                      u64 num_bytes);
  89
  90 static noinline int
  91 block_group_cache_done(struct btrfs_block_group_cache *cache)
  92 {
  93         smp_mb();
  94         return cache->cached == BTRFS_CACHE_FINISHED ||
  95                 cache->cached == BTRFS_CACHE_ERROR;
  96 }
  97
  98 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  99 {
 100         return (cache->flags & bits) == bits;
 101 }
 102
 103 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 104 {
 105         atomic_inc(&cache->count);
 106 }
 107
 108 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 109 {
 110         if (atomic_dec_and_test(&cache->count)) {
 111                 WARN_ON(cache->pinned > 0);
 112                 WARN_ON(cache->reserved > 0);
 113
 114                 /*
 115                  * If not empty, someone is still holding mutex of
 116                  * full_stripe_lock, which can only be released by caller.
 117                  * And it will definitely cause use-after-free when caller
 118                  * tries to release full stripe lock.
 119                  *
 120                  * No better way to resolve, but only to warn.
 121                  */
 122                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 123                 kfree(cache->free_space_ctl);
 124                 kfree(cache);
 125         }
 126 }
 127
 128 /*
 129  * this adds the block group to the fs_info rb tree for the block group
 130  * cache
 131  */
 132 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 133                                 struct btrfs_block_group_cache *block_group)
 134 {
 135         struct rb_node **p;
 136         struct rb_node *parent = NULL;
 137         struct btrfs_block_group_cache *cache;
 138
 139         spin_lock(&info->block_group_cache_lock);
 140         p = &info->block_group_cache_tree.rb_node;
 141
 142         while (*p) {
 143                 parent = *p;
 144                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 145                                  cache_node);
 146                 if (block_group->key.objectid < cache->key.objectid) {
 147                         p = &(*p)->rb_left;
 148                 } else if (block_group->key.objectid > cache->key.objectid) {
 149                         p = &(*p)->rb_right;
 150                 } else {
 151                         spin_unlock(&info->block_group_cache_lock);
 152                         return -EEXIST;
 153                 }
 154         }
 155
 156         rb_link_node(&block_group->cache_node, parent, p);
 157         rb_insert_color(&block_group->cache_node,
 158                         &info->block_group_cache_tree);
 159
 160         if (info->first_logical_byte > block_group->key.objectid)
 161                 info->first_logical_byte = block_group->key.objectid;
 162
 163         spin_unlock(&info->block_group_cache_lock);
 164
 165         return 0;
 166 }
 167
 168 /*
 169  * This will return the block group at or after bytenr if contains is 0, else
 170  * it will return the block group that contains the bytenr
 171  */
 172 static struct btrfs_block_group_cache *
 173 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 174                               int contains)
 175 {
 176         struct btrfs_block_group_cache *cache, *ret = NULL;
 177         struct rb_node *n;
 178         u64 end, start;
 179
 180         spin_lock(&info->block_group_cache_lock);
 181         n = info->block_group_cache_tree.rb_node;
 182
 183         while (n) {
 184                 cache = rb_entry(n, struct btrfs_block_group_cache,
 185                                  cache_node);
 186                 end = cache->key.objectid + cache->key.offset - 1;
 187                 start = cache->key.objectid;
 188
 189                 if (bytenr < start) {
 190                         if (!contains && (!ret || start < ret->key.objectid))
 191                                 ret = cache;
 192                         n = n->rb_left;
 193                 } else if (bytenr > start) {
 194                         if (contains && bytenr <= end) {
 195                                 ret = cache;
 196                                 break;
 197                         }
 198                         n = n->rb_right;
 199                 } else {
 200                         ret = cache;
 201                         break;
 202                 }
 203         }
 204         if (ret) {
 205                 btrfs_get_block_group(ret);
 206                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 207                         info->first_logical_byte = ret->key.objectid;
 208         }
 209         spin_unlock(&info->block_group_cache_lock);
 210
 211         return ret;
 212 }
 213
 214 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 215                                u64 start, u64 num_bytes)
 216 {
 217         u64 end = start + num_bytes - 1;
 218         set_extent_bits(&fs_info->freed_extents[0],
 219                         start, end, EXTENT_UPTODATE);
 220         set_extent_bits(&fs_info->freed_extents[1],
 221                         start, end, EXTENT_UPTODATE);
 222         return 0;
 223 }
 224
 225 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
 226                                   struct btrfs_block_group_cache *cache)
 227 {
 228         u64 start, end;
 229
 230         start = cache->key.objectid;
 231         end = start + cache->key.offset - 1;
 232
 233         clear_extent_bits(&fs_info->freed_extents[0],
 234                           start, end, EXTENT_UPTODATE);
 235         clear_extent_bits(&fs_info->freed_extents[1],
 236                           start, end, EXTENT_UPTODATE);
 237 }
 238
 239 static int exclude_super_stripes(struct btrfs_fs_info *fs_info,
 240                                  struct btrfs_block_group_cache *cache)
 241 {
 242         u64 bytenr;
 243         u64 *logical;
 244         int stripe_len;
 245         int i, nr, ret;
 246
 247         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 248                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 249                 cache->bytes_super += stripe_len;
 250                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 251                                           stripe_len);
 252                 if (ret)
 253                         return ret;
 254         }
 255
 256         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 257                 bytenr = btrfs_sb_offset(i);
 258                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 259                                        bytenr, 0, &logical, &nr, &stripe_len);
 260                 if (ret)
 261                         return ret;
 262
 263                 while (nr--) {
 264                         u64 start, len;
 265
 266                         if (logical[nr] > cache->key.objectid +
 267                             cache->key.offset)
 268                                 continue;
 269
 270                         if (logical[nr] + stripe_len <= cache->key.objectid)
 271                                 continue;
 272
 273                         start = logical[nr];
 274                         if (start < cache->key.objectid) {
 275                                 start = cache->key.objectid;
 276                                 len = (logical[nr] + stripe_len) - start;
 277                         } else {
 278                                 len = min_t(u64, stripe_len,
 279                                             cache->key.objectid +
 280                                             cache->key.offset - start);
 281                         }
 282
 283                         cache->bytes_super += len;
 284                         ret = add_excluded_extent(fs_info, start, len);
 285                         if (ret) {
 286                                 kfree(logical);
 287                                 return ret;
 288                         }
 289                 }
 290
 291                 kfree(logical);
 292         }
 293         return 0;
 294 }
 295
 296 static struct btrfs_caching_control *
 297 get_caching_control(struct btrfs_block_group_cache *cache)
 298 {
 299         struct btrfs_caching_control *ctl;
 300
 301         spin_lock(&cache->lock);
 302         if (!cache->caching_ctl) {
 303                 spin_unlock(&cache->lock);
 304                 return NULL;
 305         }
 306
 307         ctl = cache->caching_ctl;
 308         refcount_inc(&ctl->count);
 309         spin_unlock(&cache->lock);
 310         return ctl;
 311 }
 312
 313 static void put_caching_control(struct btrfs_caching_control *ctl)
 314 {
 315         if (refcount_dec_and_test(&ctl->count))
 316                 kfree(ctl);
 317 }
 318
 319 #ifdef CONFIG_BTRFS_DEBUG
 320 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 321 {
 322         struct btrfs_fs_info *fs_info = block_group->fs_info;
 323         u64 start = block_group->key.objectid;
 324         u64 len = block_group->key.offset;
 325         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 326                 fs_info->nodesize : fs_info->sectorsize;
 327         u64 step = chunk << 1;
 328
 329         while (len > chunk) {
 330                 btrfs_remove_free_space(block_group, start, chunk);
 331                 start += step;
 332                 if (len < step)
 333                         len = 0;
 334                 else
 335                         len -= step;
 336         }
 337 }
 338 #endif
 339
 340 /*
 341  * this is only called by cache_block_group, since we could have freed extents
 342  * we need to check the pinned_extents for any extents that can't be used yet
 343  * since their free space will be released as soon as the transaction commits.
 344  */
 345 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 346                        struct btrfs_fs_info *info, u64 start, u64 end)
 347 {
 348         u64 extent_start, extent_end, size, total_added = 0;
 349         int ret;
 350
 351         while (start < end) {
 352                 ret = find_first_extent_bit(info->pinned_extents, start,
 353                                             &extent_start, &extent_end,
 354                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 355                                             NULL);
 356                 if (ret)
 357                         break;
 358
 359                 if (extent_start <= start) {
 360                         start = extent_end + 1;
 361                 } else if (extent_start > start && extent_start < end) {
 362                         size = extent_start - start;
 363                         total_added += size;
 364                         ret = btrfs_add_free_space(block_group, start,
 365                                                    size);
 366                         BUG_ON(ret); /* -ENOMEM or logic error */
 367                         start = extent_end + 1;
 368                 } else {
 369                         break;
 370                 }
 371         }
 372
 373         if (start < end) {
 374                 size = end - start;
 375                 total_added += size;
 376                 ret = btrfs_add_free_space(block_group, start, size);
 377                 BUG_ON(ret); /* -ENOMEM or logic error */
 378         }
 379
 380         return total_added;
 381 }
 382
 383 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 384 {
 385         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 386         struct btrfs_fs_info *fs_info = block_group->fs_info;
 387         struct btrfs_root *extent_root = fs_info->extent_root;
 388         struct btrfs_path *path;
 389         struct extent_buffer *leaf;
 390         struct btrfs_key key;
 391         u64 total_found = 0;
 392         u64 last = 0;
 393         u32 nritems;
 394         int ret;
 395         bool wakeup = true;
 396
 397         path = btrfs_alloc_path();
 398         if (!path)
 399                 return -ENOMEM;
 400
 401         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 402
 403 #ifdef CONFIG_BTRFS_DEBUG
 404         /*
 405          * If we're fragmenting we don't want to make anybody think we can
 406          * allocate from this block group until we've had a chance to fragment
 407          * the free space.
 408          */
 409         if (btrfs_should_fragment_free_space(block_group))
 410                 wakeup = false;
 411 #endif
 412         /*
 413          * We don't want to deadlock with somebody trying to allocate a new
 414          * extent for the extent root while also trying to search the extent
 415          * root to add free space.  So we skip locking and search the commit
 416          * root, since its read-only
 417          */
 418         path->skip_locking = 1;
 419         path->search_commit_root = 1;
 420         path->reada = READA_FORWARD;
 421
 422         key.objectid = last;
 423         key.offset = 0;
 424         key.type = BTRFS_EXTENT_ITEM_KEY;
 425
 426 next:
 427         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 428         if (ret < 0)
 429                 goto out;
 430
 431         leaf = path->nodes[0];
 432         nritems = btrfs_header_nritems(leaf);
 433
 434         while (1) {
 435                 if (btrfs_fs_closing(fs_info) > 1) {
 436                         last = (u64)-1;
 437                         break;
 438                 }
 439
 440                 if (path->slots[0] < nritems) {
 441                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 442                 } else {
 443                         ret = find_next_key(path, 0, &key);
 444                         if (ret)
 445                                 break;
 446
 447                         if (need_resched() ||
 448                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 449                                 if (wakeup)
 450                                         caching_ctl->progress = last;
 451                                 btrfs_release_path(path);
 452                                 up_read(&fs_info->commit_root_sem);
 453                                 mutex_unlock(&caching_ctl->mutex);
 454                                 cond_resched();
 455                                 mutex_lock(&caching_ctl->mutex);
 456                                 down_read(&fs_info->commit_root_sem);
 457                                 goto next;
 458                         }
 459
 460                         ret = btrfs_next_leaf(extent_root, path);
 461                         if (ret < 0)
 462                                 goto out;
 463                         if (ret)
 464                                 break;
 465                         leaf = path->nodes[0];
 466                         nritems = btrfs_header_nritems(leaf);
 467                         continue;
 468                 }
 469
 470                 if (key.objectid < last) {
 471                         key.objectid = last;
 472                         key.offset = 0;
 473                         key.type = BTRFS_EXTENT_ITEM_KEY;
 474
 475                         if (wakeup)
 476                                 caching_ctl->progress = last;
 477                         btrfs_release_path(path);
 478                         goto next;
 479                 }
 480
 481                 if (key.objectid < block_group->key.objectid) {
 482                         path->slots[0]++;
 483                         continue;
 484                 }
 485
 486                 if (key.objectid >= block_group->key.objectid +
 487                     block_group->key.offset)
 488                         break;
 489
 490                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 491                     key.type == BTRFS_METADATA_ITEM_KEY) {
 492                         total_found += add_new_free_space(block_group,
 493                                                           fs_info, last,
 494                                                           key.objectid);
 495                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 496                                 last = key.objectid +
 497                                         fs_info->nodesize;
 498                         else
 499                                 last = key.objectid + key.offset;
 500
 501                         if (total_found > CACHING_CTL_WAKE_UP) {
 502                                 total_found = 0;
 503                                 if (wakeup)
 504                                         wake_up(&caching_ctl->wait);
 505                         }
 506                 }
 507                 path->slots[0]++;
 508         }
 509         ret = 0;
 510
 511         total_found += add_new_free_space(block_group, fs_info, last,
 512                                           block_group->key.objectid +
 513                                           block_group->key.offset);
 514         caching_ctl->progress = (u64)-1;
 515
 516 out:
 517         btrfs_free_path(path);
 518         return ret;
 519 }
 520
 521 static noinline void caching_thread(struct btrfs_work *work)
 522 {
 523         struct btrfs_block_group_cache *block_group;
 524         struct btrfs_fs_info *fs_info;
 525         struct btrfs_caching_control *caching_ctl;
 526         int ret;
 527
 528         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 529         block_group = caching_ctl->block_group;
 530         fs_info = block_group->fs_info;
 531
 532         mutex_lock(&caching_ctl->mutex);
 533         down_read(&fs_info->commit_root_sem);
 534
 535         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 536                 ret = load_free_space_tree(caching_ctl);
 537         else
 538                 ret = load_extent_tree_free(caching_ctl);
 539
 540         spin_lock(&block_group->lock);
 541         block_group->caching_ctl = NULL;
 542         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 543         spin_unlock(&block_group->lock);
 544
 545 #ifdef CONFIG_BTRFS_DEBUG
 546         if (btrfs_should_fragment_free_space(block_group)) {
 547                 u64 bytes_used;
 548
 549                 spin_lock(&block_group->space_info->lock);
 550                 spin_lock(&block_group->lock);
 551                 bytes_used = block_group->key.offset -
 552                         btrfs_block_group_used(&block_group->item);
 553                 block_group->space_info->bytes_used += bytes_used >> 1;
 554                 spin_unlock(&block_group->lock);
 555                 spin_unlock(&block_group->space_info->lock);
 556                 fragment_free_space(block_group);
 557         }
 558 #endif
 559
 560         caching_ctl->progress = (u64)-1;
 561
 562         up_read(&fs_info->commit_root_sem);
 563         free_excluded_extents(fs_info, block_group);
 564         mutex_unlock(&caching_ctl->mutex);
 565
 566         wake_up(&caching_ctl->wait);
 567
 568         put_caching_control(caching_ctl);
 569         btrfs_put_block_group(block_group);
 570 }
 571
 572 static int cache_block_group(struct btrfs_block_group_cache *cache,
 573                              int load_cache_only)
 574 {
 575         DEFINE_WAIT(wait);
 576         struct btrfs_fs_info *fs_info = cache->fs_info;
 577         struct btrfs_caching_control *caching_ctl;
 578         int ret = 0;
 579
 580         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 581         if (!caching_ctl)
 582                 return -ENOMEM;
 583
 584         INIT_LIST_HEAD(&caching_ctl->list);
 585         mutex_init(&caching_ctl->mutex);
 586         init_waitqueue_head(&caching_ctl->wait);
 587         caching_ctl->block_group = cache;
 588         caching_ctl->progress = cache->key.objectid;
 589         refcount_set(&caching_ctl->count, 1);
 590         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 591                         caching_thread, NULL, NULL);
 592
 593         spin_lock(&cache->lock);
 594         /*
 595          * This should be a rare occasion, but this could happen I think in the
 596          * case where one thread starts to load the space cache info, and then
 597          * some other thread starts a transaction commit which tries to do an
 598          * allocation while the other thread is still loading the space cache
 599          * info.  The previous loop should have kept us from choosing this block
 600          * group, but if we've moved to the state where we will wait on caching
 601          * block groups we need to first check if we're doing a fast load here,
 602          * so we can wait for it to finish, otherwise we could end up allocating
 603          * from a block group who's cache gets evicted for one reason or
 604          * another.
 605          */
 606         while (cache->cached == BTRFS_CACHE_FAST) {
 607                 struct btrfs_caching_control *ctl;
 608
 609                 ctl = cache->caching_ctl;
 610                 refcount_inc(&ctl->count);
 611                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 612                 spin_unlock(&cache->lock);
 613
 614                 schedule();
 615
 616                 finish_wait(&ctl->wait, &wait);
 617                 put_caching_control(ctl);
 618                 spin_lock(&cache->lock);
 619         }
 620
 621         if (cache->cached != BTRFS_CACHE_NO) {
 622                 spin_unlock(&cache->lock);
 623                 kfree(caching_ctl);
 624                 return 0;
 625         }
 626         WARN_ON(cache->caching_ctl);
 627         cache->caching_ctl = caching_ctl;
 628         cache->cached = BTRFS_CACHE_FAST;
 629         spin_unlock(&cache->lock);
 630
 631         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 632                 mutex_lock(&caching_ctl->mutex);
 633                 ret = load_free_space_cache(fs_info, cache);
 634
 635                 spin_lock(&cache->lock);
 636                 if (ret == 1) {
 637                         cache->caching_ctl = NULL;
 638                         cache->cached = BTRFS_CACHE_FINISHED;
 639                         cache->last_byte_to_unpin = (u64)-1;
 640                         caching_ctl->progress = (u64)-1;
 641                 } else {
 642                         if (load_cache_only) {
 643                                 cache->caching_ctl = NULL;
 644                                 cache->cached = BTRFS_CACHE_NO;
 645                         } else {
 646                                 cache->cached = BTRFS_CACHE_STARTED;
 647                                 cache->has_caching_ctl = 1;
 648                         }
 649                 }
 650                 spin_unlock(&cache->lock);
 651 #ifdef CONFIG_BTRFS_DEBUG
 652                 if (ret == 1 &&
 653                     btrfs_should_fragment_free_space(cache)) {
 654                         u64 bytes_used;
 655
 656                         spin_lock(&cache->space_info->lock);
 657                         spin_lock(&cache->lock);
 658                         bytes_used = cache->key.offset -
 659                                 btrfs_block_group_used(&cache->item);
 660                         cache->space_info->bytes_used += bytes_used >> 1;
 661                         spin_unlock(&cache->lock);
 662                         spin_unlock(&cache->space_info->lock);
 663                         fragment_free_space(cache);
 664                 }
 665 #endif
 666                 mutex_unlock(&caching_ctl->mutex);
 667
 668                 wake_up(&caching_ctl->wait);
 669                 if (ret == 1) {
 670                         put_caching_control(caching_ctl);
 671                         free_excluded_extents(fs_info, cache);
 672                         return 0;
 673                 }
 674         } else {
 675                 /*
 676                  * We're either using the free space tree or no caching at all.
 677                  * Set cached to the appropriate value and wakeup any waiters.
 678                  */
 679                 spin_lock(&cache->lock);
 680                 if (load_cache_only) {
 681                         cache->caching_ctl = NULL;
 682                         cache->cached = BTRFS_CACHE_NO;
 683                 } else {
 684                         cache->cached = BTRFS_CACHE_STARTED;
 685                         cache->has_caching_ctl = 1;
 686                 }
 687                 spin_unlock(&cache->lock);
 688                 wake_up(&caching_ctl->wait);
 689         }
 690
 691         if (load_cache_only) {
 692                 put_caching_control(caching_ctl);
 693                 return 0;
 694         }
 695
 696         down_write(&fs_info->commit_root_sem);
 697         refcount_inc(&caching_ctl->count);
 698         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 699         up_write(&fs_info->commit_root_sem);
 700
 701         btrfs_get_block_group(cache);
 702
 703         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 704
 705         return ret;
 706 }
 707
 708 /*
 709  * return the block group that starts at or after bytenr
 710  */
 711 static struct btrfs_block_group_cache *
 712 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 713 {
 714         return block_group_cache_tree_search(info, bytenr, 0);
 715 }
 716
 717 /*
 718  * return the block group that contains the given bytenr
 719  */
 720 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 721                                                  struct btrfs_fs_info *info,
 722                                                  u64 bytenr)
 723 {
 724         return block_group_cache_tree_search(info, bytenr, 1);
 725 }
 726
 727 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 728                                                   u64 flags)
 729 {
 730         struct list_head *head = &info->space_info;
 731         struct btrfs_space_info *found;
 732
 733         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 734
 735         rcu_read_lock();
 736         list_for_each_entry_rcu(found, head, list) {
 737                 if (found->flags & flags) {
 738                         rcu_read_unlock();
 739                         return found;
 740                 }
 741         }
 742         rcu_read_unlock();
 743         return NULL;
 744 }
 745
 746 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 747                              u64 owner, u64 root_objectid)
 748 {
 749         struct btrfs_space_info *space_info;
 750         u64 flags;
 751
 752         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 753                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 754                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 755                 else
 756                         flags = BTRFS_BLOCK_GROUP_METADATA;
 757         } else {
 758                 flags = BTRFS_BLOCK_GROUP_DATA;
 759         }
 760
 761         space_info = __find_space_info(fs_info, flags);
 762         ASSERT(space_info);
 763         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
 764 }
 765
 766 /*
 767  * after adding space to the filesystem, we need to clear the full flags
 768  * on all the space infos.
 769  */
 770 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 771 {
 772         struct list_head *head = &info->space_info;
 773         struct btrfs_space_info *found;
 774
 775         rcu_read_lock();
 776         list_for_each_entry_rcu(found, head, list)
 777                 found->full = 0;
 778         rcu_read_unlock();
 779 }
 780
 781 /* simple helper to search for an existing data extent at a given offset */
 782 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 783 {
 784         int ret;
 785         struct btrfs_key key;
 786         struct btrfs_path *path;
 787
 788         path = btrfs_alloc_path();
 789         if (!path)
 790                 return -ENOMEM;
 791
 792         key.objectid = start;
 793         key.offset = len;
 794         key.type = BTRFS_EXTENT_ITEM_KEY;
 795         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 796         btrfs_free_path(path);
 797         return ret;
 798 }
 799
 800 /*
 801  * helper function to lookup reference count and flags of a tree block.
 802  *
 803  * the head node for delayed ref is used to store the sum of all the
 804  * reference count modifications queued up in the rbtree. the head
 805  * node may also store the extent flags to set. This way you can check
 806  * to see what the reference count and extent flags would be if all of
 807  * the delayed refs are not processed.
 808  */
 809 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 810                              struct btrfs_fs_info *fs_info, u64 bytenr,
 811                              u64 offset, int metadata, u64 *refs, u64 *flags)
 812 {
 813         struct btrfs_delayed_ref_head *head;
 814         struct btrfs_delayed_ref_root *delayed_refs;
 815         struct btrfs_path *path;
 816         struct btrfs_extent_item *ei;
 817         struct extent_buffer *leaf;
 818         struct btrfs_key key;
 819         u32 item_size;
 820         u64 num_refs;
 821         u64 extent_flags;
 822         int ret;
 823
 824         /*
 825          * If we don't have skinny metadata, don't bother doing anything
 826          * different
 827          */
 828         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 829                 offset = fs_info->nodesize;
 830                 metadata = 0;
 831         }
 832
 833         path = btrfs_alloc_path();
 834         if (!path)
 835                 return -ENOMEM;
 836
 837         if (!trans) {
 838                 path->skip_locking = 1;
 839                 path->search_commit_root = 1;
 840         }
 841
 842 search_again:
 843         key.objectid = bytenr;
 844         key.offset = offset;
 845         if (metadata)
 846                 key.type = BTRFS_METADATA_ITEM_KEY;
 847         else
 848                 key.type = BTRFS_EXTENT_ITEM_KEY;
 849
 850         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 851         if (ret < 0)
 852                 goto out_free;
 853
 854         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 855                 if (path->slots[0]) {
 856                         path->slots[0]--;
 857                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 858                                               path->slots[0]);
 859                         if (key.objectid == bytenr &&
 860                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 861                             key.offset == fs_info->nodesize)
 862                                 ret = 0;
 863                 }
 864         }
 865
 866         if (ret == 0) {
 867                 leaf = path->nodes[0];
 868                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 869                 if (item_size >= sizeof(*ei)) {
 870                         ei = btrfs_item_ptr(leaf, path->slots[0],
 871                                             struct btrfs_extent_item);
 872                         num_refs = btrfs_extent_refs(leaf, ei);
 873                         extent_flags = btrfs_extent_flags(leaf, ei);
 874                 } else {
 875 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 876                         struct btrfs_extent_item_v0 *ei0;
 877                         BUG_ON(item_size != sizeof(*ei0));
 878                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 879                                              struct btrfs_extent_item_v0);
 880                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 881                         /* FIXME: this isn't correct for data */
 882                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 883 #else
 884                         BUG();
 885 #endif
 886                 }
 887                 BUG_ON(num_refs == 0);
 888         } else {
 889                 num_refs = 0;
 890                 extent_flags = 0;
 891                 ret = 0;
 892         }
 893
 894         if (!trans)
 895                 goto out;
 896
 897         delayed_refs = &trans->transaction->delayed_refs;
 898         spin_lock(&delayed_refs->lock);
 899         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 900         if (head) {
 901                 if (!mutex_trylock(&head->mutex)) {
 902                         refcount_inc(&head->refs);
 903                         spin_unlock(&delayed_refs->lock);
 904
 905                         btrfs_release_path(path);
 906
 907                         /*
 908                          * Mutex was contended, block until it's released and try
 909                          * again
 910                          */
 911                         mutex_lock(&head->mutex);
 912                         mutex_unlock(&head->mutex);
 913                         btrfs_put_delayed_ref_head(head);
 914                         goto search_again;
 915                 }
 916                 spin_lock(&head->lock);
 917                 if (head->extent_op && head->extent_op->update_flags)
 918                         extent_flags |= head->extent_op->flags_to_set;
 919                 else
 920                         BUG_ON(num_refs == 0);
 921
 922                 num_refs += head->ref_mod;
 923                 spin_unlock(&head->lock);
 924                 mutex_unlock(&head->mutex);
 925         }
 926         spin_unlock(&delayed_refs->lock);
 927 out:
 928         WARN_ON(num_refs == 0);
 929         if (refs)
 930                 *refs = num_refs;
 931         if (flags)
 932                 *flags = extent_flags;
 933 out_free:
 934         btrfs_free_path(path);
 935         return ret;
 936 }
 937
 938 /*
 939  * Back reference rules.  Back refs have three main goals:
 940  *
 941  * 1) differentiate between all holders of references to an extent so that
 942  *    when a reference is dropped we can make sure it was a valid reference
 943  *    before freeing the extent.
 944  *
 945  * 2) Provide enough information to quickly find the holders of an extent
 946  *    if we notice a given block is corrupted or bad.
 947  *
 948  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 949  *    maintenance.  This is actually the same as #2, but with a slightly
 950  *    different use case.
 951  *
 952  * There are two kinds of back refs. The implicit back refs is optimized
 953  * for pointers in non-shared tree blocks. For a given pointer in a block,
 954  * back refs of this kind provide information about the block's owner tree
 955  * and the pointer's key. These information allow us to find the block by
 956  * b-tree searching. The full back refs is for pointers in tree blocks not
 957  * referenced by their owner trees. The location of tree block is recorded
 958  * in the back refs. Actually the full back refs is generic, and can be
 959  * used in all cases the implicit back refs is used. The major shortcoming
 960  * of the full back refs is its overhead. Every time a tree block gets
 961  * COWed, we have to update back refs entry for all pointers in it.
 962  *
 963  * For a newly allocated tree block, we use implicit back refs for
 964  * pointers in it. This means most tree related operations only involve
 965  * implicit back refs. For a tree block created in old transaction, the
 966  * only way to drop a reference to it is COW it. So we can detect the
 967  * event that tree block loses its owner tree's reference and do the
 968  * back refs conversion.
 969  *
 970  * When a tree block is COWed through a tree, there are four cases:
 971  *
 972  * The reference count of the block is one and the tree is the block's
 973  * owner tree. Nothing to do in this case.
 974  *
 975  * The reference count of the block is one and the tree is not the
 976  * block's owner tree. In this case, full back refs is used for pointers
 977  * in the block. Remove these full back refs, add implicit back refs for
 978  * every pointers in the new block.
 979  *
 980  * The reference count of the block is greater than one and the tree is
 981  * the block's owner tree. In this case, implicit back refs is used for
 982  * pointers in the block. Add full back refs for every pointers in the
 983  * block, increase lower level extents' reference counts. The original
 984  * implicit back refs are entailed to the new block.
 985  *
 986  * The reference count of the block is greater than one and the tree is
 987  * not the block's owner tree. Add implicit back refs for every pointer in
 988  * the new block, increase lower level extents' reference count.
 989  *
 990  * Back Reference Key composing:
 991  *
 992  * The key objectid corresponds to the first byte in the extent,
 993  * The key type is used to differentiate between types of back refs.
 994  * There are different meanings of the key offset for different types
 995  * of back refs.
 996  *
 997  * File extents can be referenced by:
 998  *
 999  * - multiple snapshots, subvolumes, or different generations in one subvol
1000  * - different files inside a single subvolume
1001  * - different offsets inside a file (bookend extents in file.c)
1002  *
1003  * The extent ref structure for the implicit back refs has fields for:
1004  *
1005  * - Objectid of the subvolume root
1006  * - objectid of the file holding the reference
1007  * - original offset in the file
1008  * - how many bookend extents
1009  *
1010  * The key offset for the implicit back refs is hash of the first
1011  * three fields.
1012  *
1013  * The extent ref structure for the full back refs has field for:
1014  *
1015  * - number of pointers in the tree leaf
1016  *
1017  * The key offset for the implicit back refs is the first byte of
1018  * the tree leaf
1019  *
1020  * When a file extent is allocated, The implicit back refs is used.
1021  * the fields are filled in:
1022  *
1023  *     (root_key.objectid, inode objectid, offset in file, 1)
1024  *
1025  * When a file extent is removed file truncation, we find the
1026  * corresponding implicit back refs and check the following fields:
1027  *
1028  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1029  *
1030  * Btree extents can be referenced by:
1031  *
1032  * - Different subvolumes
1033  *
1034  * Both the implicit back refs and the full back refs for tree blocks
1035  * only consist of key. The key offset for the implicit back refs is
1036  * objectid of block's owner tree. The key offset for the full back refs
1037  * is the first byte of parent block.
1038  *
1039  * When implicit back refs is used, information about the lowest key and
1040  * level of the tree block are required. These information are stored in
1041  * tree block info structure.
1042  */
1043
1044 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1045 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1046                                   struct btrfs_fs_info *fs_info,
1047                                   struct btrfs_path *path,
1048                                   u64 owner, u32 extra_size)
1049 {
1050         struct btrfs_root *root = fs_info->extent_root;
1051         struct btrfs_extent_item *item;
1052         struct btrfs_extent_item_v0 *ei0;
1053         struct btrfs_extent_ref_v0 *ref0;
1054         struct btrfs_tree_block_info *bi;
1055         struct extent_buffer *leaf;
1056         struct btrfs_key key;
1057         struct btrfs_key found_key;
1058         u32 new_size = sizeof(*item);
1059         u64 refs;
1060         int ret;
1061
1062         leaf = path->nodes[0];
1063         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1064
1065         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1066         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1067                              struct btrfs_extent_item_v0);
1068         refs = btrfs_extent_refs_v0(leaf, ei0);
1069
1070         if (owner == (u64)-1) {
1071                 while (1) {
1072                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1073                                 ret = btrfs_next_leaf(root, path);
1074                                 if (ret < 0)
1075                                         return ret;
1076                                 BUG_ON(ret > 0); /* Corruption */
1077                                 leaf = path->nodes[0];
1078                         }
1079                         btrfs_item_key_to_cpu(leaf, &found_key,
1080                                               path->slots[0]);
1081                         BUG_ON(key.objectid != found_key.objectid);
1082                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1083                                 path->slots[0]++;
1084                                 continue;
1085                         }
1086                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1087                                               struct btrfs_extent_ref_v0);
1088                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1089                         break;
1090                 }
1091         }
1092         btrfs_release_path(path);
1093
1094         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1095                 new_size += sizeof(*bi);
1096
1097         new_size -= sizeof(*ei0);
1098         ret = btrfs_search_slot(trans, root, &key, path,
1099                                 new_size + extra_size, 1);
1100         if (ret < 0)
1101                 return ret;
1102         BUG_ON(ret); /* Corruption */
1103
1104         btrfs_extend_item(fs_info, path, new_size);
1105
1106         leaf = path->nodes[0];
1107         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1108         btrfs_set_extent_refs(leaf, item, refs);
1109         /* FIXME: get real generation */
1110         btrfs_set_extent_generation(leaf, item, 0);
1111         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1112                 btrfs_set_extent_flags(leaf, item,
1113                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1114                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1115                 bi = (struct btrfs_tree_block_info *)(item + 1);
1116                 /* FIXME: get first key of the block */
1117                 memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
1118                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1119         } else {
1120                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1121         }
1122         btrfs_mark_buffer_dirty(leaf);
1123         return 0;
1124 }
1125 #endif
1126
1127 /*
1128  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1129  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1130  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1131  */
1132 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1133                                      struct btrfs_extent_inline_ref *iref,
1134                                      enum btrfs_inline_ref_type is_data)
1135 {
1136         int type = btrfs_extent_inline_ref_type(eb, iref);
1137         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1138
1139         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1140             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1141             type == BTRFS_SHARED_DATA_REF_KEY ||
1142             type == BTRFS_EXTENT_DATA_REF_KEY) {
1143                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1144                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1145                                 return type;
1146                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1147                                 ASSERT(eb->fs_info);
1148                                 /*
1149                                  * Every shared one has parent tree
1150                                  * block, which must be aligned to
1151                                  * nodesize.
1152                                  */
1153                                 if (offset &&
1154                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1155                                         return type;
1156                         }
1157                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1158                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1159                                 return type;
1160                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1161                                 ASSERT(eb->fs_info);
1162                                 /*
1163                                  * Every shared one has parent tree
1164                                  * block, which must be aligned to
1165                                  * nodesize.
1166                                  */
1167                                 if (offset &&
1168                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1169                                         return type;
1170                         }
1171                 } else {
1172                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1173                         return type;
1174                 }
1175         }
1176
1177         btrfs_print_leaf((struct extent_buffer *)eb);
1178         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1179                   eb->start, type);
1180         WARN_ON(1);
1181
1182         return BTRFS_REF_TYPE_INVALID;
1183 }
1184
1185 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1186 {
1187         u32 high_crc = ~(u32)0;
1188         u32 low_crc = ~(u32)0;
1189         __le64 lenum;
1190
1191         lenum = cpu_to_le64(root_objectid);
1192         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1193         lenum = cpu_to_le64(owner);
1194         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1195         lenum = cpu_to_le64(offset);
1196         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1197
1198         return ((u64)high_crc << 31) ^ (u64)low_crc;
1199 }
1200
1201 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1202                                      struct btrfs_extent_data_ref *ref)
1203 {
1204         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1205                                     btrfs_extent_data_ref_objectid(leaf, ref),
1206                                     btrfs_extent_data_ref_offset(leaf, ref));
1207 }
1208
1209 static int match_extent_data_ref(struct extent_buffer *leaf,
1210                                  struct btrfs_extent_data_ref *ref,
1211                                  u64 root_objectid, u64 owner, u64 offset)
1212 {
1213         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1214             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1215             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1216                 return 0;
1217         return 1;
1218 }
1219
1220 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1221                                            struct btrfs_fs_info *fs_info,
1222                                            struct btrfs_path *path,
1223                                            u64 bytenr, u64 parent,
1224                                            u64 root_objectid,
1225                                            u64 owner, u64 offset)
1226 {
1227         struct btrfs_root *root = fs_info->extent_root;
1228         struct btrfs_key key;
1229         struct btrfs_extent_data_ref *ref;
1230         struct extent_buffer *leaf;
1231         u32 nritems;
1232         int ret;
1233         int recow;
1234         int err = -ENOENT;
1235
1236         key.objectid = bytenr;
1237         if (parent) {
1238                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1239                 key.offset = parent;
1240         } else {
1241                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1242                 key.offset = hash_extent_data_ref(root_objectid,
1243                                                   owner, offset);
1244         }
1245 again:
1246         recow = 0;
1247         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1248         if (ret < 0) {
1249                 err = ret;
1250                 goto fail;
1251         }
1252
1253         if (parent) {
1254                 if (!ret)
1255                         return 0;
1256 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1257                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1258                 btrfs_release_path(path);
1259                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1260                 if (ret < 0) {
1261                         err = ret;
1262                         goto fail;
1263                 }
1264                 if (!ret)
1265                         return 0;
1266 #endif
1267                 goto fail;
1268         }
1269
1270         leaf = path->nodes[0];
1271         nritems = btrfs_header_nritems(leaf);
1272         while (1) {
1273                 if (path->slots[0] >= nritems) {
1274                         ret = btrfs_next_leaf(root, path);
1275                         if (ret < 0)
1276                                 err = ret;
1277                         if (ret)
1278                                 goto fail;
1279
1280                         leaf = path->nodes[0];
1281                         nritems = btrfs_header_nritems(leaf);
1282                         recow = 1;
1283                 }
1284
1285                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1286                 if (key.objectid != bytenr ||
1287                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1288                         goto fail;
1289
1290                 ref = btrfs_item_ptr(leaf, path->slots[0],
1291                                      struct btrfs_extent_data_ref);
1292
1293                 if (match_extent_data_ref(leaf, ref, root_objectid,
1294                                           owner, offset)) {
1295                         if (recow) {
1296                                 btrfs_release_path(path);
1297                                 goto again;
1298                         }
1299                         err = 0;
1300                         break;
1301                 }
1302                 path->slots[0]++;
1303         }
1304 fail:
1305         return err;
1306 }
1307
1308 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1309                                            struct btrfs_fs_info *fs_info,
1310                                            struct btrfs_path *path,
1311                                            u64 bytenr, u64 parent,
1312                                            u64 root_objectid, u64 owner,
1313                                            u64 offset, int refs_to_add)
1314 {
1315         struct btrfs_root *root = fs_info->extent_root;
1316         struct btrfs_key key;
1317         struct extent_buffer *leaf;
1318         u32 size;
1319         u32 num_refs;
1320         int ret;
1321
1322         key.objectid = bytenr;
1323         if (parent) {
1324                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1325                 key.offset = parent;
1326                 size = sizeof(struct btrfs_shared_data_ref);
1327         } else {
1328                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1329                 key.offset = hash_extent_data_ref(root_objectid,
1330                                                   owner, offset);
1331                 size = sizeof(struct btrfs_extent_data_ref);
1332         }
1333
1334         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1335         if (ret && ret != -EEXIST)
1336                 goto fail;
1337
1338         leaf = path->nodes[0];
1339         if (parent) {
1340                 struct btrfs_shared_data_ref *ref;
1341                 ref = btrfs_item_ptr(leaf, path->slots[0],
1342                                      struct btrfs_shared_data_ref);
1343                 if (ret == 0) {
1344                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1345                 } else {
1346                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1347                         num_refs += refs_to_add;
1348                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1349                 }
1350         } else {
1351                 struct btrfs_extent_data_ref *ref;
1352                 while (ret == -EEXIST) {
1353                         ref = btrfs_item_ptr(leaf, path->slots[0],
1354                                              struct btrfs_extent_data_ref);
1355                         if (match_extent_data_ref(leaf, ref, root_objectid,
1356                                                   owner, offset))
1357                                 break;
1358                         btrfs_release_path(path);
1359                         key.offset++;
1360                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1361                                                       size);
1362                         if (ret && ret != -EEXIST)
1363                                 goto fail;
1364
1365                         leaf = path->nodes[0];
1366                 }
1367                 ref = btrfs_item_ptr(leaf, path->slots[0],
1368                                      struct btrfs_extent_data_ref);
1369                 if (ret == 0) {
1370                         btrfs_set_extent_data_ref_root(leaf, ref,
1371                                                        root_objectid);
1372                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1373                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1374                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1375                 } else {
1376                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1377                         num_refs += refs_to_add;
1378                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1379                 }
1380         }
1381         btrfs_mark_buffer_dirty(leaf);
1382         ret = 0;
1383 fail:
1384         btrfs_release_path(path);
1385         return ret;
1386 }
1387
1388 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1389                                            struct btrfs_fs_info *fs_info,
1390                                            struct btrfs_path *path,
1391                                            int refs_to_drop, int *last_ref)
1392 {
1393         struct btrfs_key key;
1394         struct btrfs_extent_data_ref *ref1 = NULL;
1395         struct btrfs_shared_data_ref *ref2 = NULL;
1396         struct extent_buffer *leaf;
1397         u32 num_refs = 0;
1398         int ret = 0;
1399
1400         leaf = path->nodes[0];
1401         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1402
1403         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1404                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1405                                       struct btrfs_extent_data_ref);
1406                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1407         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1408                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1409                                       struct btrfs_shared_data_ref);
1410                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1411 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1412         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1413                 struct btrfs_extent_ref_v0 *ref0;
1414                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1415                                       struct btrfs_extent_ref_v0);
1416                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1417 #endif
1418         } else {
1419                 BUG();
1420         }
1421
1422         BUG_ON(num_refs < refs_to_drop);
1423         num_refs -= refs_to_drop;
1424
1425         if (num_refs == 0) {
1426                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1427                 *last_ref = 1;
1428         } else {
1429                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1430                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1431                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1432                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1433 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1434                 else {
1435                         struct btrfs_extent_ref_v0 *ref0;
1436                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1437                                         struct btrfs_extent_ref_v0);
1438                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1439                 }
1440 #endif
1441                 btrfs_mark_buffer_dirty(leaf);
1442         }
1443         return ret;
1444 }
1445
1446 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1447                                           struct btrfs_extent_inline_ref *iref)
1448 {
1449         struct btrfs_key key;
1450         struct extent_buffer *leaf;
1451         struct btrfs_extent_data_ref *ref1;
1452         struct btrfs_shared_data_ref *ref2;
1453         u32 num_refs = 0;
1454         int type;
1455
1456         leaf = path->nodes[0];
1457         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1458         if (iref) {
1459                 /*
1460                  * If type is invalid, we should have bailed out earlier than
1461                  * this call.
1462                  */
1463                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1464                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1465                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1466                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1467                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1468                 } else {
1469                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1470                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1471                 }
1472         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1473                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1474                                       struct btrfs_extent_data_ref);
1475                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1476         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1477                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1478                                       struct btrfs_shared_data_ref);
1479                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1480 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1481         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1482                 struct btrfs_extent_ref_v0 *ref0;
1483                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1484                                       struct btrfs_extent_ref_v0);
1485                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1486 #endif
1487         } else {
1488                 WARN_ON(1);
1489         }
1490         return num_refs;
1491 }
1492
1493 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1494                                           struct btrfs_fs_info *fs_info,
1495                                           struct btrfs_path *path,
1496                                           u64 bytenr, u64 parent,
1497                                           u64 root_objectid)
1498 {
1499         struct btrfs_root *root = fs_info->extent_root;
1500         struct btrfs_key key;
1501         int ret;
1502
1503         key.objectid = bytenr;
1504         if (parent) {
1505                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1506                 key.offset = parent;
1507         } else {
1508                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1509                 key.offset = root_objectid;
1510         }
1511
1512         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1513         if (ret > 0)
1514                 ret = -ENOENT;
1515 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1516         if (ret == -ENOENT && parent) {
1517                 btrfs_release_path(path);
1518                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1519                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1520                 if (ret > 0)
1521                         ret = -ENOENT;
1522         }
1523 #endif
1524         return ret;
1525 }
1526
1527 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1528                                           struct btrfs_fs_info *fs_info,
1529                                           struct btrfs_path *path,
1530                                           u64 bytenr, u64 parent,
1531                                           u64 root_objectid)
1532 {
1533         struct btrfs_key key;
1534         int ret;
1535
1536         key.objectid = bytenr;
1537         if (parent) {
1538                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1539                 key.offset = parent;
1540         } else {
1541                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1542                 key.offset = root_objectid;
1543         }
1544
1545         ret = btrfs_insert_empty_item(trans, fs_info->extent_root,
1546                                       path, &key, 0);
1547         btrfs_release_path(path);
1548         return ret;
1549 }
1550
1551 static inline int extent_ref_type(u64 parent, u64 owner)
1552 {
1553         int type;
1554         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1555                 if (parent > 0)
1556                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1557                 else
1558                         type = BTRFS_TREE_BLOCK_REF_KEY;
1559         } else {
1560                 if (parent > 0)
1561                         type = BTRFS_SHARED_DATA_REF_KEY;
1562                 else
1563                         type = BTRFS_EXTENT_DATA_REF_KEY;
1564         }
1565         return type;
1566 }
1567
1568 static int find_next_key(struct btrfs_path *path, int level,
1569                          struct btrfs_key *key)
1570
1571 {
1572         for (; level < BTRFS_MAX_LEVEL; level++) {
1573                 if (!path->nodes[level])
1574                         break;
1575                 if (path->slots[level] + 1 >=
1576                     btrfs_header_nritems(path->nodes[level]))
1577                         continue;
1578                 if (level == 0)
1579                         btrfs_item_key_to_cpu(path->nodes[level], key,
1580                                               path->slots[level] + 1);
1581                 else
1582                         btrfs_node_key_to_cpu(path->nodes[level], key,
1583                                               path->slots[level] + 1);
1584                 return 0;
1585         }
1586         return 1;
1587 }
1588
1589 /*
1590  * look for inline back ref. if back ref is found, *ref_ret is set
1591  * to the address of inline back ref, and 0 is returned.
1592  *
1593  * if back ref isn't found, *ref_ret is set to the address where it
1594  * should be inserted, and -ENOENT is returned.
1595  *
1596  * if insert is true and there are too many inline back refs, the path
1597  * points to the extent item, and -EAGAIN is returned.
1598  *
1599  * NOTE: inline back refs are ordered in the same way that back ref
1600  *       items in the tree are ordered.
1601  */
1602 static noinline_for_stack
1603 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1604                                  struct btrfs_fs_info *fs_info,
1605                                  struct btrfs_path *path,
1606                                  struct btrfs_extent_inline_ref **ref_ret,
1607                                  u64 bytenr, u64 num_bytes,
1608                                  u64 parent, u64 root_objectid,
1609                                  u64 owner, u64 offset, int insert)
1610 {
1611         struct btrfs_root *root = fs_info->extent_root;
1612         struct btrfs_key key;
1613         struct extent_buffer *leaf;
1614         struct btrfs_extent_item *ei;
1615         struct btrfs_extent_inline_ref *iref;
1616         u64 flags;
1617         u64 item_size;
1618         unsigned long ptr;
1619         unsigned long end;
1620         int extra_size;
1621         int type;
1622         int want;
1623         int ret;
1624         int err = 0;
1625         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1626         int needed;
1627
1628         key.objectid = bytenr;
1629         key.type = BTRFS_EXTENT_ITEM_KEY;
1630         key.offset = num_bytes;
1631
1632         want = extent_ref_type(parent, owner);
1633         if (insert) {
1634                 extra_size = btrfs_extent_inline_ref_size(want);
1635                 path->keep_locks = 1;
1636         } else
1637                 extra_size = -1;
1638
1639         /*
1640          * Owner is our parent level, so we can just add one to get the level
1641          * for the block we are interested in.
1642          */
1643         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1644                 key.type = BTRFS_METADATA_ITEM_KEY;
1645                 key.offset = owner;
1646         }
1647
1648 again:
1649         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1650         if (ret < 0) {
1651                 err = ret;
1652                 goto out;
1653         }
1654
1655         /*
1656          * We may be a newly converted file system which still has the old fat
1657          * extent entries for metadata, so try and see if we have one of those.
1658          */
1659         if (ret > 0 && skinny_metadata) {
1660                 skinny_metadata = false;
1661                 if (path->slots[0]) {
1662                         path->slots[0]--;
1663                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1664                                               path->slots[0]);
1665                         if (key.objectid == bytenr &&
1666                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1667                             key.offset == num_bytes)
1668                                 ret = 0;
1669                 }
1670                 if (ret) {
1671                         key.objectid = bytenr;
1672                         key.type = BTRFS_EXTENT_ITEM_KEY;
1673                         key.offset = num_bytes;
1674                         btrfs_release_path(path);
1675                         goto again;
1676                 }
1677         }
1678
1679         if (ret && !insert) {
1680                 err = -ENOENT;
1681                 goto out;
1682         } else if (WARN_ON(ret)) {
1683                 err = -EIO;
1684                 goto out;
1685         }
1686
1687         leaf = path->nodes[0];
1688         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1689 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1690         if (item_size < sizeof(*ei)) {
1691                 if (!insert) {
1692                         err = -ENOENT;
1693                         goto out;
1694                 }
1695                 ret = convert_extent_item_v0(trans, fs_info, path, owner,
1696                                              extra_size);
1697                 if (ret < 0) {
1698                         err = ret;
1699                         goto out;
1700                 }
1701                 leaf = path->nodes[0];
1702                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1703         }
1704 #endif
1705         BUG_ON(item_size < sizeof(*ei));
1706
1707         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1708         flags = btrfs_extent_flags(leaf, ei);
1709
1710         ptr = (unsigned long)(ei + 1);
1711         end = (unsigned long)ei + item_size;
1712
1713         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1714                 ptr += sizeof(struct btrfs_tree_block_info);
1715                 BUG_ON(ptr > end);
1716         }
1717
1718         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1719                 needed = BTRFS_REF_TYPE_DATA;
1720         else
1721                 needed = BTRFS_REF_TYPE_BLOCK;
1722
1723         err = -ENOENT;
1724         while (1) {
1725                 if (ptr >= end) {
1726                         WARN_ON(ptr > end);
1727                         break;
1728                 }
1729                 iref = (struct btrfs_extent_inline_ref *)ptr;
1730                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1731                 if (type == BTRFS_REF_TYPE_INVALID) {
1732                         err = -EINVAL;
1733                         goto out;
1734                 }
1735
1736                 if (want < type)
1737                         break;
1738                 if (want > type) {
1739                         ptr += btrfs_extent_inline_ref_size(type);
1740                         continue;
1741                 }
1742
1743                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1744                         struct btrfs_extent_data_ref *dref;
1745                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1746                         if (match_extent_data_ref(leaf, dref, root_objectid,
1747                                                   owner, offset)) {
1748                                 err = 0;
1749                                 break;
1750                         }
1751                         if (hash_extent_data_ref_item(leaf, dref) <
1752                             hash_extent_data_ref(root_objectid, owner, offset))
1753                                 break;
1754                 } else {
1755                         u64 ref_offset;
1756                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1757                         if (parent > 0) {
1758                                 if (parent == ref_offset) {
1759                                         err = 0;
1760                                         break;
1761                                 }
1762                                 if (ref_offset < parent)
1763                                         break;
1764                         } else {
1765                                 if (root_objectid == ref_offset) {
1766                                         err = 0;
1767                                         break;
1768                                 }
1769                                 if (ref_offset < root_objectid)
1770                                         break;
1771                         }
1772                 }
1773                 ptr += btrfs_extent_inline_ref_size(type);
1774         }
1775         if (err == -ENOENT && insert) {
1776                 if (item_size + extra_size >=
1777                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1778                         err = -EAGAIN;
1779                         goto out;
1780                 }
1781                 /*
1782                  * To add new inline back ref, we have to make sure
1783                  * there is no corresponding back ref item.
1784                  * For simplicity, we just do not add new inline back
1785                  * ref if there is any kind of item for this block
1786                  */
1787                 if (find_next_key(path, 0, &key) == 0 &&
1788                     key.objectid == bytenr &&
1789                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1790                         err = -EAGAIN;
1791                         goto out;
1792                 }
1793         }
1794         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1795 out:
1796         if (insert) {
1797                 path->keep_locks = 0;
1798                 btrfs_unlock_up_safe(path, 1);
1799         }
1800         return err;
1801 }
1802
1803 /*
1804  * helper to add new inline back ref
1805  */
1806 static noinline_for_stack
1807 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1808                                  struct btrfs_path *path,
1809                                  struct btrfs_extent_inline_ref *iref,
1810                                  u64 parent, u64 root_objectid,
1811                                  u64 owner, u64 offset, int refs_to_add,
1812                                  struct btrfs_delayed_extent_op *extent_op)
1813 {
1814         struct extent_buffer *leaf;
1815         struct btrfs_extent_item *ei;
1816         unsigned long ptr;
1817         unsigned long end;
1818         unsigned long item_offset;
1819         u64 refs;
1820         int size;
1821         int type;
1822
1823         leaf = path->nodes[0];
1824         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1825         item_offset = (unsigned long)iref - (unsigned long)ei;
1826
1827         type = extent_ref_type(parent, owner);
1828         size = btrfs_extent_inline_ref_size(type);
1829
1830         btrfs_extend_item(fs_info, path, size);
1831
1832         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1833         refs = btrfs_extent_refs(leaf, ei);
1834         refs += refs_to_add;
1835         btrfs_set_extent_refs(leaf, ei, refs);
1836         if (extent_op)
1837                 __run_delayed_extent_op(extent_op, leaf, ei);
1838
1839         ptr = (unsigned long)ei + item_offset;
1840         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1841         if (ptr < end - size)
1842                 memmove_extent_buffer(leaf, ptr + size, ptr,
1843                                       end - size - ptr);
1844
1845         iref = (struct btrfs_extent_inline_ref *)ptr;
1846         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1847         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1848                 struct btrfs_extent_data_ref *dref;
1849                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1850                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1851                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1852                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1853                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1854         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1855                 struct btrfs_shared_data_ref *sref;
1856                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1857                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1858                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1859         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1860                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1861         } else {
1862                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1863         }
1864         btrfs_mark_buffer_dirty(leaf);
1865 }
1866
1867 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1868                                  struct btrfs_fs_info *fs_info,
1869                                  struct btrfs_path *path,
1870                                  struct btrfs_extent_inline_ref **ref_ret,
1871                                  u64 bytenr, u64 num_bytes, u64 parent,
1872                                  u64 root_objectid, u64 owner, u64 offset)
1873 {
1874         int ret;
1875
1876         ret = lookup_inline_extent_backref(trans, fs_info, path, ref_ret,
1877                                            bytenr, num_bytes, parent,
1878                                            root_objectid, owner, offset, 0);
1879         if (ret != -ENOENT)
1880                 return ret;
1881
1882         btrfs_release_path(path);
1883         *ref_ret = NULL;
1884
1885         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1886                 ret = lookup_tree_block_ref(trans, fs_info, path, bytenr,
1887                                             parent, root_objectid);
1888         } else {
1889                 ret = lookup_extent_data_ref(trans, fs_info, path, bytenr,
1890                                              parent, root_objectid, owner,
1891                                              offset);
1892         }
1893         return ret;
1894 }
1895
1896 /*
1897  * helper to update/remove inline back ref
1898  */
1899 static noinline_for_stack
1900 void update_inline_extent_backref(struct btrfs_fs_info *fs_info,
1901                                   struct btrfs_path *path,
1902                                   struct btrfs_extent_inline_ref *iref,
1903                                   int refs_to_mod,
1904                                   struct btrfs_delayed_extent_op *extent_op,
1905                                   int *last_ref)
1906 {
1907         struct extent_buffer *leaf;
1908         struct btrfs_extent_item *ei;
1909         struct btrfs_extent_data_ref *dref = NULL;
1910         struct btrfs_shared_data_ref *sref = NULL;
1911         unsigned long ptr;
1912         unsigned long end;
1913         u32 item_size;
1914         int size;
1915         int type;
1916         u64 refs;
1917
1918         leaf = path->nodes[0];
1919         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1920         refs = btrfs_extent_refs(leaf, ei);
1921         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1922         refs += refs_to_mod;
1923         btrfs_set_extent_refs(leaf, ei, refs);
1924         if (extent_op)
1925                 __run_delayed_extent_op(extent_op, leaf, ei);
1926
1927         /*
1928          * If type is invalid, we should have bailed out after
1929          * lookup_inline_extent_backref().
1930          */
1931         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1932         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1933
1934         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1935                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1936                 refs = btrfs_extent_data_ref_count(leaf, dref);
1937         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1938                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1939                 refs = btrfs_shared_data_ref_count(leaf, sref);
1940         } else {
1941                 refs = 1;
1942                 BUG_ON(refs_to_mod != -1);
1943         }
1944
1945         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1946         refs += refs_to_mod;
1947
1948         if (refs > 0) {
1949                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1950                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1951                 else
1952                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1953         } else {
1954                 *last_ref = 1;
1955                 size =  btrfs_extent_inline_ref_size(type);
1956                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1957                 ptr = (unsigned long)iref;
1958                 end = (unsigned long)ei + item_size;
1959                 if (ptr + size < end)
1960                         memmove_extent_buffer(leaf, ptr, ptr + size,
1961                                               end - ptr - size);
1962                 item_size -= size;
1963                 btrfs_truncate_item(fs_info, path, item_size, 1);
1964         }
1965         btrfs_mark_buffer_dirty(leaf);
1966 }
1967
1968 static noinline_for_stack
1969 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1970                                  struct btrfs_fs_info *fs_info,
1971                                  struct btrfs_path *path,
1972                                  u64 bytenr, u64 num_bytes, u64 parent,
1973                                  u64 root_objectid, u64 owner,
1974                                  u64 offset, int refs_to_add,
1975                                  struct btrfs_delayed_extent_op *extent_op)
1976 {
1977         struct btrfs_extent_inline_ref *iref;
1978         int ret;
1979
1980         ret = lookup_inline_extent_backref(trans, fs_info, path, &iref,
1981                                            bytenr, num_bytes, parent,
1982                                            root_objectid, owner, offset, 1);
1983         if (ret == 0) {
1984                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1985                 update_inline_extent_backref(fs_info, path, iref,
1986                                              refs_to_add, extent_op, NULL);
1987         } else if (ret == -ENOENT) {
1988                 setup_inline_extent_backref(fs_info, path, iref, parent,
1989                                             root_objectid, owner, offset,
1990                                             refs_to_add, extent_op);
1991                 ret = 0;
1992         }
1993         return ret;
1994 }
1995
1996 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1997                                  struct btrfs_fs_info *fs_info,
1998                                  struct btrfs_path *path,
1999                                  u64 bytenr, u64 parent, u64 root_objectid,
2000                                  u64 owner, u64 offset, int refs_to_add)
2001 {
2002         int ret;
2003         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2004                 BUG_ON(refs_to_add != 1);
2005                 ret = insert_tree_block_ref(trans, fs_info, path, bytenr,
2006                                             parent, root_objectid);
2007         } else {
2008                 ret = insert_extent_data_ref(trans, fs_info, path, bytenr,
2009                                              parent, root_objectid,
2010                                              owner, offset, refs_to_add);
2011         }
2012         return ret;
2013 }
2014
2015 static int remove_extent_backref(struct btrfs_trans_handle *trans,
2016                                  struct btrfs_fs_info *fs_info,
2017                                  struct btrfs_path *path,
2018                                  struct btrfs_extent_inline_ref *iref,
2019                                  int refs_to_drop, int is_data, int *last_ref)
2020 {
2021         int ret = 0;
2022
2023         BUG_ON(!is_data && refs_to_drop != 1);
2024         if (iref) {
2025                 update_inline_extent_backref(fs_info, path, iref,
2026                                              -refs_to_drop, NULL, last_ref);
2027         } else if (is_data) {
2028                 ret = remove_extent_data_ref(trans, fs_info, path, refs_to_drop,
2029                                              last_ref);
2030         } else {
2031                 *last_ref = 1;
2032                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
2033         }
2034         return ret;
2035 }
2036
2037 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
2038 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
2039                                u64 *discarded_bytes)
2040 {
2041         int j, ret = 0;
2042         u64 bytes_left, end;
2043         u64 aligned_start = ALIGN(start, 1 << 9);
2044
2045         if (WARN_ON(start != aligned_start)) {
2046                 len -= aligned_start - start;
2047                 len = round_down(len, 1 << 9);
2048                 start = aligned_start;
2049         }
2050
2051         *discarded_bytes = 0;
2052
2053         if (!len)
2054                 return 0;
2055
2056         end = start + len;
2057         bytes_left = len;
2058
2059         /* Skip any superblocks on this device. */
2060         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
2061                 u64 sb_start = btrfs_sb_offset(j);
2062                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
2063                 u64 size = sb_start - start;
2064
2065                 if (!in_range(sb_start, start, bytes_left) &&
2066                     !in_range(sb_end, start, bytes_left) &&
2067                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
2068                         continue;
2069
2070                 /*
2071                  * Superblock spans beginning of range.  Adjust start and
2072                  * try again.
2073                  */
2074                 if (sb_start <= start) {
2075                         start += sb_end - start;
2076                         if (start > end) {
2077                                 bytes_left = 0;
2078                                 break;
2079                         }
2080                         bytes_left = end - start;
2081                         continue;
2082                 }
2083
2084                 if (size) {
2085                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2086                                                    GFP_NOFS, 0);
2087                         if (!ret)
2088                                 *discarded_bytes += size;
2089                         else if (ret != -EOPNOTSUPP)
2090                                 return ret;
2091                 }
2092
2093                 start = sb_end;
2094                 if (start > end) {
2095                         bytes_left = 0;
2096                         break;
2097                 }
2098                 bytes_left = end - start;
2099         }
2100
2101         if (bytes_left) {
2102                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2103                                            GFP_NOFS, 0);
2104                 if (!ret)
2105                         *discarded_bytes += bytes_left;
2106         }
2107         return ret;
2108 }
2109
2110 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
2111                          u64 num_bytes, u64 *actual_bytes)
2112 {
2113         int ret;
2114         u64 discarded_bytes = 0;
2115         struct btrfs_bio *bbio = NULL;
2116
2117
2118         /*
2119          * Avoid races with device replace and make sure our bbio has devices
2120          * associated to its stripes that don't go away while we are discarding.
2121          */
2122         btrfs_bio_counter_inc_blocked(fs_info);
2123         /* Tell the block device(s) that the sectors can be discarded */
2124         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
2125                               &bbio, 0);
2126         /* Error condition is -ENOMEM */
2127         if (!ret) {
2128                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2129                 int i;
2130
2131
2132                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2133                         u64 bytes;
2134                         struct request_queue *req_q;
2135
2136                         if (!stripe->dev->bdev) {
2137                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
2138                                 continue;
2139                         }
2140                         req_q = bdev_get_queue(stripe->dev->bdev);
2141                         if (!blk_queue_discard(req_q))
2142                                 continue;
2143
2144                         ret = btrfs_issue_discard(stripe->dev->bdev,
2145                                                   stripe->physical,
2146                                                   stripe->length,
2147                                                   &bytes);
2148                         if (!ret)
2149                                 discarded_bytes += bytes;
2150                         else if (ret != -EOPNOTSUPP)
2151                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2152
2153                         /*
2154                          * Just in case we get back EOPNOTSUPP for some reason,
2155                          * just ignore the return value so we don't screw up
2156                          * people calling discard_extent.
2157                          */
2158                         ret = 0;
2159                 }
2160                 btrfs_put_bbio(bbio);
2161         }
2162         btrfs_bio_counter_dec(fs_info);
2163
2164         if (actual_bytes)
2165                 *actual_bytes = discarded_bytes;
2166
2167
2168         if (ret == -EOPNOTSUPP)
2169                 ret = 0;
2170         return ret;
2171 }
2172
2173 /* Can return -ENOMEM */
2174 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2175                          struct btrfs_root *root,
2176                          u64 bytenr, u64 num_bytes, u64 parent,
2177                          u64 root_objectid, u64 owner, u64 offset)
2178 {
2179         struct btrfs_fs_info *fs_info = root->fs_info;
2180         int old_ref_mod, new_ref_mod;
2181         int ret;
2182
2183         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2184                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2185
2186         btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
2187                            owner, offset, BTRFS_ADD_DELAYED_REF);
2188
2189         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2190                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2191                                                  num_bytes, parent,
2192                                                  root_objectid, (int)owner,
2193                                                  BTRFS_ADD_DELAYED_REF, NULL,
2194                                                  &old_ref_mod, &new_ref_mod);
2195         } else {
2196                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2197                                                  num_bytes, parent,
2198                                                  root_objectid, owner, offset,
2199                                                  0, BTRFS_ADD_DELAYED_REF,
2200                                                  &old_ref_mod, &new_ref_mod);
2201         }
2202
2203         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
2204                 add_pinned_bytes(fs_info, -num_bytes, owner, root_objectid);
2205
2206         return ret;
2207 }
2208
2209 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2210                                   struct btrfs_fs_info *fs_info,
2211                                   struct btrfs_delayed_ref_node *node,
2212                                   u64 parent, u64 root_objectid,
2213                                   u64 owner, u64 offset, int refs_to_add,
2214                                   struct btrfs_delayed_extent_op *extent_op)
2215 {
2216         struct btrfs_path *path;
2217         struct extent_buffer *leaf;
2218         struct btrfs_extent_item *item;
2219         struct btrfs_key key;
2220         u64 bytenr = node->bytenr;
2221         u64 num_bytes = node->num_bytes;
2222         u64 refs;
2223         int ret;
2224
2225         path = btrfs_alloc_path();
2226         if (!path)
2227                 return -ENOMEM;
2228
2229         path->reada = READA_FORWARD;
2230         path->leave_spinning = 1;
2231         /* this will setup the path even if it fails to insert the back ref */
2232         ret = insert_inline_extent_backref(trans, fs_info, path, bytenr,
2233                                            num_bytes, parent, root_objectid,
2234                                            owner, offset,
2235                                            refs_to_add, extent_op);
2236         if ((ret < 0 && ret != -EAGAIN) || !ret)
2237                 goto out;
2238
2239         /*
2240          * Ok we had -EAGAIN which means we didn't have space to insert and
2241          * inline extent ref, so just update the reference count and add a
2242          * normal backref.
2243          */
2244         leaf = path->nodes[0];
2245         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2246         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2247         refs = btrfs_extent_refs(leaf, item);
2248         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2249         if (extent_op)
2250                 __run_delayed_extent_op(extent_op, leaf, item);
2251
2252         btrfs_mark_buffer_dirty(leaf);
2253         btrfs_release_path(path);
2254
2255         path->reada = READA_FORWARD;
2256         path->leave_spinning = 1;
2257         /* now insert the actual backref */
2258         ret = insert_extent_backref(trans, fs_info, path, bytenr, parent,
2259                                     root_objectid, owner, offset, refs_to_add);
2260         if (ret)
2261                 btrfs_abort_transaction(trans, ret);
2262 out:
2263         btrfs_free_path(path);
2264         return ret;
2265 }
2266
2267 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2268                                 struct btrfs_fs_info *fs_info,
2269                                 struct btrfs_delayed_ref_node *node,
2270                                 struct btrfs_delayed_extent_op *extent_op,
2271                                 int insert_reserved)
2272 {
2273         int ret = 0;
2274         struct btrfs_delayed_data_ref *ref;
2275         struct btrfs_key ins;
2276         u64 parent = 0;
2277         u64 ref_root = 0;
2278         u64 flags = 0;
2279
2280         ins.objectid = node->bytenr;
2281         ins.offset = node->num_bytes;
2282         ins.type = BTRFS_EXTENT_ITEM_KEY;
2283
2284         ref = btrfs_delayed_node_to_data_ref(node);
2285         trace_run_delayed_data_ref(fs_info, node, ref, node->action);
2286
2287         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2288                 parent = ref->parent;
2289         ref_root = ref->root;
2290
2291         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2292                 if (extent_op)
2293                         flags |= extent_op->flags_to_set;
2294                 ret = alloc_reserved_file_extent(trans, fs_info,
2295                                                  parent, ref_root, flags,
2296                                                  ref->objectid, ref->offset,
2297                                                  &ins, node->ref_mod);
2298         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2299                 ret = __btrfs_inc_extent_ref(trans, fs_info, node, parent,
2300                                              ref_root, ref->objectid,
2301                                              ref->offset, node->ref_mod,
2302                                              extent_op);
2303         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2304                 ret = __btrfs_free_extent(trans, fs_info, node, parent,
2305                                           ref_root, ref->objectid,
2306                                           ref->offset, node->ref_mod,
2307                                           extent_op);
2308         } else {
2309                 BUG();
2310         }
2311         return ret;
2312 }
2313
2314 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2315                                     struct extent_buffer *leaf,
2316                                     struct btrfs_extent_item *ei)
2317 {
2318         u64 flags = btrfs_extent_flags(leaf, ei);
2319         if (extent_op->update_flags) {
2320                 flags |= extent_op->flags_to_set;
2321                 btrfs_set_extent_flags(leaf, ei, flags);
2322         }
2323
2324         if (extent_op->update_key) {
2325                 struct btrfs_tree_block_info *bi;
2326                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2327                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2328                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2329         }
2330 }
2331
2332 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2333                                  struct btrfs_fs_info *fs_info,
2334                                  struct btrfs_delayed_ref_head *head,
2335                                  struct btrfs_delayed_extent_op *extent_op)
2336 {
2337         struct btrfs_key key;
2338         struct btrfs_path *path;
2339         struct btrfs_extent_item *ei;
2340         struct extent_buffer *leaf;
2341         u32 item_size;
2342         int ret;
2343         int err = 0;
2344         int metadata = !extent_op->is_data;
2345
2346         if (trans->aborted)
2347                 return 0;
2348
2349         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2350                 metadata = 0;
2351
2352         path = btrfs_alloc_path();
2353         if (!path)
2354                 return -ENOMEM;
2355
2356         key.objectid = head->bytenr;
2357
2358         if (metadata) {
2359                 key.type = BTRFS_METADATA_ITEM_KEY;
2360                 key.offset = extent_op->level;
2361         } else {
2362                 key.type = BTRFS_EXTENT_ITEM_KEY;
2363                 key.offset = head->num_bytes;
2364         }
2365
2366 again:
2367         path->reada = READA_FORWARD;
2368         path->leave_spinning = 1;
2369         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2370         if (ret < 0) {
2371                 err = ret;
2372                 goto out;
2373         }
2374         if (ret > 0) {
2375                 if (metadata) {
2376                         if (path->slots[0] > 0) {
2377                                 path->slots[0]--;
2378                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2379                                                       path->slots[0]);
2380                                 if (key.objectid == head->bytenr &&
2381                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2382                                     key.offset == head->num_bytes)
2383                                         ret = 0;
2384                         }
2385                         if (ret > 0) {
2386                                 btrfs_release_path(path);
2387                                 metadata = 0;
2388
2389                                 key.objectid = head->bytenr;
2390                                 key.offset = head->num_bytes;
2391                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2392                                 goto again;
2393                         }
2394                 } else {
2395                         err = -EIO;
2396                         goto out;
2397                 }
2398         }
2399
2400         leaf = path->nodes[0];
2401         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2402 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2403         if (item_size < sizeof(*ei)) {
2404                 ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
2405                 if (ret < 0) {
2406                         err = ret;
2407                         goto out;
2408                 }
2409                 leaf = path->nodes[0];
2410                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2411         }
2412 #endif
2413         BUG_ON(item_size < sizeof(*ei));
2414         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2415         __run_delayed_extent_op(extent_op, leaf, ei);
2416
2417         btrfs_mark_buffer_dirty(leaf);
2418 out:
2419         btrfs_free_path(path);
2420         return err;
2421 }
2422
2423 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2424                                 struct btrfs_fs_info *fs_info,
2425                                 struct btrfs_delayed_ref_node *node,
2426                                 struct btrfs_delayed_extent_op *extent_op,
2427                                 int insert_reserved)
2428 {
2429         int ret = 0;
2430         struct btrfs_delayed_tree_ref *ref;
2431         struct btrfs_key ins;
2432         u64 parent = 0;
2433         u64 ref_root = 0;
2434         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
2435
2436         ref = btrfs_delayed_node_to_tree_ref(node);
2437         trace_run_delayed_tree_ref(fs_info, node, ref, node->action);
2438
2439         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2440                 parent = ref->parent;
2441         ref_root = ref->root;
2442
2443         ins.objectid = node->bytenr;
2444         if (skinny_metadata) {
2445                 ins.offset = ref->level;
2446                 ins.type = BTRFS_METADATA_ITEM_KEY;
2447         } else {
2448                 ins.offset = node->num_bytes;
2449                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2450         }
2451
2452         if (node->ref_mod != 1) {
2453                 btrfs_err(fs_info,
2454         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2455                           node->bytenr, node->ref_mod, node->action, ref_root,
2456                           parent);
2457                 return -EIO;
2458         }
2459         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2460                 BUG_ON(!extent_op || !extent_op->update_flags);
2461                 ret = alloc_reserved_tree_block(trans, fs_info,
2462                                                 parent, ref_root,
2463                                                 extent_op->flags_to_set,
2464                                                 &extent_op->key,
2465                                                 ref->level, &ins);
2466         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2467                 ret = __btrfs_inc_extent_ref(trans, fs_info, node,
2468                                              parent, ref_root,
2469                                              ref->level, 0, 1,
2470                                              extent_op);
2471         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2472                 ret = __btrfs_free_extent(trans, fs_info, node,
2473                                           parent, ref_root,
2474                                           ref->level, 0, 1, extent_op);
2475         } else {
2476                 BUG();
2477         }
2478         return ret;
2479 }
2480
2481 /* helper function to actually process a single delayed ref entry */
2482 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2483                                struct btrfs_fs_info *fs_info,
2484                                struct btrfs_delayed_ref_node *node,
2485                                struct btrfs_delayed_extent_op *extent_op,
2486                                int insert_reserved)
2487 {
2488         int ret = 0;
2489
2490         if (trans->aborted) {
2491                 if (insert_reserved)
2492                         btrfs_pin_extent(fs_info, node->bytenr,
2493                                          node->num_bytes, 1);
2494                 return 0;
2495         }
2496
2497         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2498             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2499                 ret = run_delayed_tree_ref(trans, fs_info, node, extent_op,
2500                                            insert_reserved);
2501         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2502                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2503                 ret = run_delayed_data_ref(trans, fs_info, node, extent_op,
2504                                            insert_reserved);
2505         else
2506                 BUG();
2507         return ret;
2508 }
2509
2510 static inline struct btrfs_delayed_ref_node *
2511 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2512 {
2513         struct btrfs_delayed_ref_node *ref;
2514
2515         if (RB_EMPTY_ROOT(&head->ref_tree))
2516                 return NULL;
2517
2518         /*
2519          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2520          * This is to prevent a ref count from going down to zero, which deletes
2521          * the extent item from the extent tree, when there still are references
2522          * to add, which would fail because they would not find the extent item.
2523          */
2524         if (!list_empty(&head->ref_add_list))
2525                 return list_first_entry(&head->ref_add_list,
2526                                 struct btrfs_delayed_ref_node, add_list);
2527
2528         ref = rb_entry(rb_first(&head->ref_tree),
2529                        struct btrfs_delayed_ref_node, ref_node);
2530         ASSERT(list_empty(&ref->add_list));
2531         return ref;
2532 }
2533
2534 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2535                                       struct btrfs_delayed_ref_head *head)
2536 {
2537         spin_lock(&delayed_refs->lock);
2538         head->processing = 0;
2539         delayed_refs->num_heads_ready++;
2540         spin_unlock(&delayed_refs->lock);
2541         btrfs_delayed_ref_unlock(head);
2542 }
2543
2544 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2545                              struct btrfs_fs_info *fs_info,
2546                              struct btrfs_delayed_ref_head *head)
2547 {
2548         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2549         int ret;
2550
2551         if (!extent_op)
2552                 return 0;
2553         head->extent_op = NULL;
2554         if (head->must_insert_reserved) {
2555                 btrfs_free_delayed_extent_op(extent_op);
2556                 return 0;
2557         }
2558         spin_unlock(&head->lock);
2559         ret = run_delayed_extent_op(trans, fs_info, head, extent_op);
2560         btrfs_free_delayed_extent_op(extent_op);
2561         return ret ? ret : 1;
2562 }
2563
2564 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2565                             struct btrfs_fs_info *fs_info,
2566                             struct btrfs_delayed_ref_head *head)
2567 {
2568         struct btrfs_delayed_ref_root *delayed_refs;
2569         int ret;
2570
2571         delayed_refs = &trans->transaction->delayed_refs;
2572
2573         ret = cleanup_extent_op(trans, fs_info, head);
2574         if (ret < 0) {
2575                 unselect_delayed_ref_head(delayed_refs, head);
2576                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2577                 return ret;
2578         } else if (ret) {
2579                 return ret;
2580         }
2581
2582         /*
2583          * Need to drop our head ref lock and re-acquire the delayed ref lock
2584          * and then re-check to make sure nobody got added.
2585          */
2586         spin_unlock(&head->lock);
2587         spin_lock(&delayed_refs->lock);
2588         spin_lock(&head->lock);
2589         if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) {
2590                 spin_unlock(&head->lock);
2591                 spin_unlock(&delayed_refs->lock);
2592                 return 1;
2593         }
2594         delayed_refs->num_heads--;
2595         rb_erase(&head->href_node, &delayed_refs->href_root);
2596         RB_CLEAR_NODE(&head->href_node);
2597         spin_unlock(&delayed_refs->lock);
2598         spin_unlock(&head->lock);
2599         atomic_dec(&delayed_refs->num_entries);
2600
2601         trace_run_delayed_ref_head(fs_info, head, 0);
2602
2603         if (head->total_ref_mod < 0) {
2604                 struct btrfs_block_group_cache *cache;
2605
2606                 cache = btrfs_lookup_block_group(fs_info, head->bytenr);
2607                 ASSERT(cache);
2608                 percpu_counter_add(&cache->space_info->total_bytes_pinned,
2609                                    -head->num_bytes);
2610                 btrfs_put_block_group(cache);
2611
2612                 if (head->is_data) {
2613                         spin_lock(&delayed_refs->lock);
2614                         delayed_refs->pending_csums -= head->num_bytes;
2615                         spin_unlock(&delayed_refs->lock);
2616                 }
2617         }
2618
2619         if (head->must_insert_reserved) {
2620                 btrfs_pin_extent(fs_info, head->bytenr,
2621                                  head->num_bytes, 1);
2622                 if (head->is_data) {
2623                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2624                                               head->num_bytes);
2625                 }
2626         }
2627
2628         /* Also free its reserved qgroup space */
2629         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2630                                       head->qgroup_reserved);
2631         btrfs_delayed_ref_unlock(head);
2632         btrfs_put_delayed_ref_head(head);
2633         return 0;
2634 }
2635
2636 /*
2637  * Returns 0 on success or if called with an already aborted transaction.
2638  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2639  */
2640 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2641                                              unsigned long nr)
2642 {
2643         struct btrfs_fs_info *fs_info = trans->fs_info;
2644         struct btrfs_delayed_ref_root *delayed_refs;
2645         struct btrfs_delayed_ref_node *ref;
2646         struct btrfs_delayed_ref_head *locked_ref = NULL;
2647         struct btrfs_delayed_extent_op *extent_op;
2648         ktime_t start = ktime_get();
2649         int ret;
2650         unsigned long count = 0;
2651         unsigned long actual_count = 0;
2652         int must_insert_reserved = 0;
2653
2654         delayed_refs = &trans->transaction->delayed_refs;
2655         while (1) {
2656                 if (!locked_ref) {
2657                         if (count >= nr)
2658                                 break;
2659
2660                         spin_lock(&delayed_refs->lock);
2661                         locked_ref = btrfs_select_ref_head(trans);
2662                         if (!locked_ref) {
2663                                 spin_unlock(&delayed_refs->lock);
2664                                 break;
2665                         }
2666
2667                         /* grab the lock that says we are going to process
2668                          * all the refs for this head */
2669                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2670                         spin_unlock(&delayed_refs->lock);
2671                         /*
2672                          * we may have dropped the spin lock to get the head
2673                          * mutex lock, and that might have given someone else
2674                          * time to free the head.  If that's true, it has been
2675                          * removed from our list and we can move on.
2676                          */
2677                         if (ret == -EAGAIN) {
2678                                 locked_ref = NULL;
2679                                 count++;
2680                                 continue;
2681                         }
2682                 }
2683
2684                 /*
2685                  * We need to try and merge add/drops of the same ref since we
2686                  * can run into issues with relocate dropping the implicit ref
2687                  * and then it being added back again before the drop can
2688                  * finish.  If we merged anything we need to re-loop so we can
2689                  * get a good ref.
2690                  * Or we can get node references of the same type that weren't
2691                  * merged when created due to bumps in the tree mod seq, and
2692                  * we need to merge them to prevent adding an inline extent
2693                  * backref before dropping it (triggering a BUG_ON at
2694                  * insert_inline_extent_backref()).
2695                  */
2696                 spin_lock(&locked_ref->lock);
2697                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2698                                          locked_ref);
2699
2700                 /*
2701                  * locked_ref is the head node, so we have to go one
2702                  * node back for any delayed ref updates
2703                  */
2704                 ref = select_delayed_ref(locked_ref);
2705
2706                 if (ref && ref->seq &&
2707                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2708                         spin_unlock(&locked_ref->lock);
2709                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2710                         locked_ref = NULL;
2711                         cond_resched();
2712                         count++;
2713                         continue;
2714                 }
2715
2716                 /*
2717                  * We're done processing refs in this ref_head, clean everything
2718                  * up and move on to the next ref_head.
2719                  */
2720                 if (!ref) {
2721                         ret = cleanup_ref_head(trans, fs_info, locked_ref);
2722                         if (ret > 0 ) {
2723                                 /* We dropped our lock, we need to loop. */
2724                                 ret = 0;
2725                                 continue;
2726                         } else if (ret) {
2727                                 return ret;
2728                         }
2729                         locked_ref = NULL;
2730                         count++;
2731                         continue;
2732                 }
2733
2734                 actual_count++;
2735                 ref->in_tree = 0;
2736                 rb_erase(&ref->ref_node, &locked_ref->ref_tree);
2737                 RB_CLEAR_NODE(&ref->ref_node);
2738                 if (!list_empty(&ref->add_list))
2739                         list_del(&ref->add_list);
2740                 /*
2741                  * When we play the delayed ref, also correct the ref_mod on
2742                  * head
2743                  */
2744                 switch (ref->action) {
2745                 case BTRFS_ADD_DELAYED_REF:
2746                 case BTRFS_ADD_DELAYED_EXTENT:
2747                         locked_ref->ref_mod -= ref->ref_mod;
2748                         break;
2749                 case BTRFS_DROP_DELAYED_REF:
2750                         locked_ref->ref_mod += ref->ref_mod;
2751                         break;
2752                 default:
2753                         WARN_ON(1);
2754                 }
2755                 atomic_dec(&delayed_refs->num_entries);
2756
2757                 /*
2758                  * Record the must-insert_reserved flag before we drop the spin
2759                  * lock.
2760                  */
2761                 must_insert_reserved = locked_ref->must_insert_reserved;
2762                 locked_ref->must_insert_reserved = 0;
2763
2764                 extent_op = locked_ref->extent_op;
2765                 locked_ref->extent_op = NULL;
2766                 spin_unlock(&locked_ref->lock);
2767
2768                 ret = run_one_delayed_ref(trans, fs_info, ref, extent_op,
2769                                           must_insert_reserved);
2770
2771                 btrfs_free_delayed_extent_op(extent_op);
2772                 if (ret) {
2773                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2774                         btrfs_put_delayed_ref(ref);
2775                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2776                                     ret);
2777                         return ret;
2778                 }
2779
2780                 btrfs_put_delayed_ref(ref);
2781                 count++;
2782                 cond_resched();
2783         }
2784
2785         /*
2786          * We don't want to include ref heads since we can have empty ref heads
2787          * and those will drastically skew our runtime down since we just do
2788          * accounting, no actual extent tree updates.
2789          */
2790         if (actual_count > 0) {
2791                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2792                 u64 avg;
2793
2794                 /*
2795                  * We weigh the current average higher than our current runtime
2796                  * to avoid large swings in the average.
2797                  */
2798                 spin_lock(&delayed_refs->lock);
2799                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2800                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2801                 spin_unlock(&delayed_refs->lock);
2802         }
2803         return 0;
2804 }
2805
2806 #ifdef SCRAMBLE_DELAYED_REFS
2807 /*
2808  * Normally delayed refs get processed in ascending bytenr order. This
2809  * correlates in most cases to the order added. To expose dependencies on this
2810  * order, we start to process the tree in the middle instead of the beginning
2811  */
2812 static u64 find_middle(struct rb_root *root)
2813 {
2814         struct rb_node *n = root->rb_node;
2815         struct btrfs_delayed_ref_node *entry;
2816         int alt = 1;
2817         u64 middle;
2818         u64 first = 0, last = 0;
2819
2820         n = rb_first(root);
2821         if (n) {
2822                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2823                 first = entry->bytenr;
2824         }
2825         n = rb_last(root);
2826         if (n) {
2827                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2828                 last = entry->bytenr;
2829         }
2830         n = root->rb_node;
2831
2832         while (n) {
2833                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2834                 WARN_ON(!entry->in_tree);
2835
2836                 middle = entry->bytenr;
2837
2838                 if (alt)
2839                         n = n->rb_left;
2840                 else
2841                         n = n->rb_right;
2842
2843                 alt = 1 - alt;
2844         }
2845         return middle;
2846 }
2847 #endif
2848
2849 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2850 {
2851         u64 num_bytes;
2852
2853         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2854                              sizeof(struct btrfs_extent_inline_ref));
2855         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2856                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2857
2858         /*
2859          * We don't ever fill up leaves all the way so multiply by 2 just to be
2860          * closer to what we're really going to want to use.
2861          */
2862         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2863 }
2864
2865 /*
2866  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2867  * would require to store the csums for that many bytes.
2868  */
2869 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2870 {
2871         u64 csum_size;
2872         u64 num_csums_per_leaf;
2873         u64 num_csums;
2874
2875         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2876         num_csums_per_leaf = div64_u64(csum_size,
2877                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2878         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2879         num_csums += num_csums_per_leaf - 1;
2880         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2881         return num_csums;
2882 }
2883
2884 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2885                                        struct btrfs_fs_info *fs_info)
2886 {
2887         struct btrfs_block_rsv *global_rsv;
2888         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2889         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2890         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2891         u64 num_bytes, num_dirty_bgs_bytes;
2892         int ret = 0;
2893
2894         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2895         num_heads = heads_to_leaves(fs_info, num_heads);
2896         if (num_heads > 1)
2897                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2898         num_bytes <<= 1;
2899         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2900                                                         fs_info->nodesize;
2901         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2902                                                              num_dirty_bgs);
2903         global_rsv = &fs_info->global_block_rsv;
2904
2905         /*
2906          * If we can't allocate any more chunks lets make sure we have _lots_ of
2907          * wiggle room since running delayed refs can create more delayed refs.
2908          */
2909         if (global_rsv->space_info->full) {
2910                 num_dirty_bgs_bytes <<= 1;
2911                 num_bytes <<= 1;
2912         }
2913
2914         spin_lock(&global_rsv->lock);
2915         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2916                 ret = 1;
2917         spin_unlock(&global_rsv->lock);
2918         return ret;
2919 }
2920
2921 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2922                                        struct btrfs_fs_info *fs_info)
2923 {
2924         u64 num_entries =
2925                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2926         u64 avg_runtime;
2927         u64 val;
2928
2929         smp_mb();
2930         avg_runtime = fs_info->avg_delayed_ref_runtime;
2931         val = num_entries * avg_runtime;
2932         if (val >= NSEC_PER_SEC)
2933                 return 1;
2934         if (val >= NSEC_PER_SEC / 2)
2935                 return 2;
2936
2937         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2938 }
2939
2940 struct async_delayed_refs {
2941         struct btrfs_root *root;
2942         u64 transid;
2943         int count;
2944         int error;
2945         int sync;
2946         struct completion wait;
2947         struct btrfs_work work;
2948 };
2949
2950 static inline struct async_delayed_refs *
2951 to_async_delayed_refs(struct btrfs_work *work)
2952 {
2953         return container_of(work, struct async_delayed_refs, work);
2954 }
2955
2956 static void delayed_ref_async_start(struct btrfs_work *work)
2957 {
2958         struct async_delayed_refs *async = to_async_delayed_refs(work);
2959         struct btrfs_trans_handle *trans;
2960         struct btrfs_fs_info *fs_info = async->root->fs_info;
2961         int ret;
2962
2963         /* if the commit is already started, we don't need to wait here */
2964         if (btrfs_transaction_blocked(fs_info))
2965                 goto done;
2966
2967         trans = btrfs_join_transaction(async->root);
2968         if (IS_ERR(trans)) {
2969                 async->error = PTR_ERR(trans);
2970                 goto done;
2971         }
2972
2973         /*
2974          * trans->sync means that when we call end_transaction, we won't
2975          * wait on delayed refs
2976          */
2977         trans->sync = true;
2978
2979         /* Don't bother flushing if we got into a different transaction */
2980         if (trans->transid > async->transid)
2981                 goto end;
2982
2983         ret = btrfs_run_delayed_refs(trans, async->count);
2984         if (ret)
2985                 async->error = ret;
2986 end:
2987         ret = btrfs_end_transaction(trans);
2988         if (ret && !async->error)
2989                 async->error = ret;
2990 done:
2991         if (async->sync)
2992                 complete(&async->wait);
2993         else
2994                 kfree(async);
2995 }
2996
2997 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2998                                  unsigned long count, u64 transid, int wait)
2999 {
3000         struct async_delayed_refs *async;
3001         int ret;
3002
3003         async = kmalloc(sizeof(*async), GFP_NOFS);
3004         if (!async)
3005                 return -ENOMEM;
3006
3007         async->root = fs_info->tree_root;
3008         async->count = count;
3009         async->error = 0;
3010         async->transid = transid;
3011         if (wait)
3012                 async->sync = 1;
3013         else
3014                 async->sync = 0;
3015         init_completion(&async->wait);
3016
3017         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
3018                         delayed_ref_async_start, NULL, NULL);
3019
3020         btrfs_queue_work(fs_info->extent_workers, &async->work);
3021
3022         if (wait) {
3023                 wait_for_completion(&async->wait);
3024                 ret = async->error;
3025                 kfree(async);
3026                 return ret;
3027         }
3028         return 0;
3029 }
3030
3031 /*
3032  * this starts processing the delayed reference count updates and
3033  * extent insertions we have queued up so far.  count can be
3034  * 0, which means to process everything in the tree at the start
3035  * of the run (but not newly added entries), or it can be some target
3036  * number you'd like to process.
3037  *
3038  * Returns 0 on success or if called with an aborted transaction
3039  * Returns <0 on error and aborts the transaction
3040  */
3041 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
3042                            unsigned long count)
3043 {
3044         struct btrfs_fs_info *fs_info = trans->fs_info;
3045         struct rb_node *node;
3046         struct btrfs_delayed_ref_root *delayed_refs;
3047         struct btrfs_delayed_ref_head *head;
3048         int ret;
3049         int run_all = count == (unsigned long)-1;
3050         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
3051
3052         /* We'll clean this up in btrfs_cleanup_transaction */
3053         if (trans->aborted)
3054                 return 0;
3055
3056         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
3057                 return 0;
3058
3059         delayed_refs = &trans->transaction->delayed_refs;
3060         if (count == 0)
3061                 count = atomic_read(&delayed_refs->num_entries) * 2;
3062
3063 again:
3064 #ifdef SCRAMBLE_DELAYED_REFS
3065         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
3066 #endif
3067         trans->can_flush_pending_bgs = false;
3068         ret = __btrfs_run_delayed_refs(trans, count);
3069         if (ret < 0) {
3070                 btrfs_abort_transaction(trans, ret);
3071                 return ret;
3072         }
3073
3074         if (run_all) {
3075                 if (!list_empty(&trans->new_bgs))
3076                         btrfs_create_pending_block_groups(trans);
3077
3078                 spin_lock(&delayed_refs->lock);
3079                 node = rb_first(&delayed_refs->href_root);
3080                 if (!node) {
3081                         spin_unlock(&delayed_refs->lock);
3082                         goto out;
3083                 }
3084                 head = rb_entry(node, struct btrfs_delayed_ref_head,
3085                                 href_node);
3086                 refcount_inc(&head->refs);
3087                 spin_unlock(&delayed_refs->lock);
3088
3089                 /* Mutex was contended, block until it's released and retry. */
3090                 mutex_lock(&head->mutex);
3091                 mutex_unlock(&head->mutex);
3092
3093                 btrfs_put_delayed_ref_head(head);
3094                 cond_resched();
3095                 goto again;
3096         }
3097 out:
3098         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3099         return 0;
3100 }
3101
3102 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3103                                 struct btrfs_fs_info *fs_info,
3104                                 u64 bytenr, u64 num_bytes, u64 flags,
3105                                 int level, int is_data)
3106 {
3107         struct btrfs_delayed_extent_op *extent_op;
3108         int ret;
3109
3110         extent_op = btrfs_alloc_delayed_extent_op();
3111         if (!extent_op)
3112                 return -ENOMEM;
3113
3114         extent_op->flags_to_set = flags;
3115         extent_op->update_flags = true;
3116         extent_op->update_key = false;
3117         extent_op->is_data = is_data ? true : false;
3118         extent_op->level = level;
3119
3120         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3121                                           num_bytes, extent_op);
3122         if (ret)
3123                 btrfs_free_delayed_extent_op(extent_op);
3124         return ret;
3125 }
3126
3127 static noinline int check_delayed_ref(struct btrfs_root *root,
3128                                       struct btrfs_path *path,
3129                                       u64 objectid, u64 offset, u64 bytenr)
3130 {
3131         struct btrfs_delayed_ref_head *head;
3132         struct btrfs_delayed_ref_node *ref;
3133         struct btrfs_delayed_data_ref *data_ref;
3134         struct btrfs_delayed_ref_root *delayed_refs;
3135         struct btrfs_transaction *cur_trans;
3136         struct rb_node *node;
3137         int ret = 0;
3138
3139         cur_trans = root->fs_info->running_transaction;
3140         if (!cur_trans)
3141                 return 0;
3142
3143         delayed_refs = &cur_trans->delayed_refs;
3144         spin_lock(&delayed_refs->lock);
3145         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3146         if (!head) {
3147                 spin_unlock(&delayed_refs->lock);
3148                 return 0;
3149         }
3150
3151         if (!mutex_trylock(&head->mutex)) {
3152                 refcount_inc(&head->refs);
3153                 spin_unlock(&delayed_refs->lock);
3154
3155                 btrfs_release_path(path);
3156
3157                 /*
3158                  * Mutex was contended, block until it's released and let
3159                  * caller try again
3160                  */
3161                 mutex_lock(&head->mutex);
3162                 mutex_unlock(&head->mutex);
3163                 btrfs_put_delayed_ref_head(head);
3164                 return -EAGAIN;
3165         }
3166         spin_unlock(&delayed_refs->lock);
3167
3168         spin_lock(&head->lock);
3169         /*
3170          * XXX: We should replace this with a proper search function in the
3171          * future.
3172          */
3173         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
3174                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3175                 /* If it's a shared ref we know a cross reference exists */
3176                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3177                         ret = 1;
3178                         break;
3179                 }
3180
3181                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3182
3183                 /*
3184                  * If our ref doesn't match the one we're currently looking at
3185                  * then we have a cross reference.
3186                  */
3187                 if (data_ref->root != root->root_key.objectid ||
3188                     data_ref->objectid != objectid ||
3189                     data_ref->offset != offset) {
3190                         ret = 1;
3191                         break;
3192                 }
3193         }
3194         spin_unlock(&head->lock);
3195         mutex_unlock(&head->mutex);
3196         return ret;
3197 }
3198
3199 static noinline int check_committed_ref(struct btrfs_root *root,
3200                                         struct btrfs_path *path,
3201                                         u64 objectid, u64 offset, u64 bytenr)
3202 {
3203         struct btrfs_fs_info *fs_info = root->fs_info;
3204         struct btrfs_root *extent_root = fs_info->extent_root;
3205         struct extent_buffer *leaf;
3206         struct btrfs_extent_data_ref *ref;
3207         struct btrfs_extent_inline_ref *iref;
3208         struct btrfs_extent_item *ei;
3209         struct btrfs_key key;
3210         u32 item_size;
3211         int type;
3212         int ret;
3213
3214         key.objectid = bytenr;
3215         key.offset = (u64)-1;
3216         key.type = BTRFS_EXTENT_ITEM_KEY;
3217
3218         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3219         if (ret < 0)
3220                 goto out;
3221         BUG_ON(ret == 0); /* Corruption */
3222
3223         ret = -ENOENT;
3224         if (path->slots[0] == 0)
3225                 goto out;
3226
3227         path->slots[0]--;
3228         leaf = path->nodes[0];
3229         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3230
3231         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3232                 goto out;
3233
3234         ret = 1;
3235         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3236 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3237         if (item_size < sizeof(*ei)) {
3238                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3239                 goto out;
3240         }
3241 #endif
3242         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3243
3244         if (item_size != sizeof(*ei) +
3245             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3246                 goto out;
3247
3248         if (btrfs_extent_generation(leaf, ei) <=
3249             btrfs_root_last_snapshot(&root->root_item))
3250                 goto out;
3251
3252         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3253
3254         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3255         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3256                 goto out;
3257
3258         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3259         if (btrfs_extent_refs(leaf, ei) !=
3260             btrfs_extent_data_ref_count(leaf, ref) ||
3261             btrfs_extent_data_ref_root(leaf, ref) !=
3262             root->root_key.objectid ||
3263             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3264             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3265                 goto out;
3266
3267         ret = 0;
3268 out:
3269         return ret;
3270 }
3271
3272 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3273                           u64 bytenr)
3274 {
3275         struct btrfs_path *path;
3276         int ret;
3277         int ret2;
3278
3279         path = btrfs_alloc_path();
3280         if (!path)
3281                 return -ENOENT;
3282
3283         do {
3284                 ret = check_committed_ref(root, path, objectid,
3285                                           offset, bytenr);
3286                 if (ret && ret != -ENOENT)
3287                         goto out;
3288
3289                 ret2 = check_delayed_ref(root, path, objectid,
3290                                          offset, bytenr);
3291         } while (ret2 == -EAGAIN);
3292
3293         if (ret2 && ret2 != -ENOENT) {
3294                 ret = ret2;
3295                 goto out;
3296         }
3297
3298         if (ret != -ENOENT || ret2 != -ENOENT)
3299                 ret = 0;
3300 out:
3301         btrfs_free_path(path);
3302         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3303                 WARN_ON(ret > 0);
3304         return ret;
3305 }
3306
3307 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3308                            struct btrfs_root *root,
3309                            struct extent_buffer *buf,
3310                            int full_backref, int inc)
3311 {
3312         struct btrfs_fs_info *fs_info = root->fs_info;
3313         u64 bytenr;
3314         u64 num_bytes;
3315         u64 parent;
3316         u64 ref_root;
3317         u32 nritems;
3318         struct btrfs_key key;
3319         struct btrfs_file_extent_item *fi;
3320         int i;
3321         int level;
3322         int ret = 0;
3323         int (*process_func)(struct btrfs_trans_handle *,
3324                             struct btrfs_root *,
3325                             u64, u64, u64, u64, u64, u64);
3326
3327
3328         if (btrfs_is_testing(fs_info))
3329                 return 0;
3330
3331         ref_root = btrfs_header_owner(buf);
3332         nritems = btrfs_header_nritems(buf);
3333         level = btrfs_header_level(buf);
3334
3335         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3336                 return 0;
3337
3338         if (inc)
3339                 process_func = btrfs_inc_extent_ref;
3340         else
3341                 process_func = btrfs_free_extent;
3342
3343         if (full_backref)
3344                 parent = buf->start;
3345         else
3346                 parent = 0;
3347
3348         for (i = 0; i < nritems; i++) {
3349                 if (level == 0) {
3350                         btrfs_item_key_to_cpu(buf, &key, i);
3351                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3352                                 continue;
3353                         fi = btrfs_item_ptr(buf, i,
3354                                             struct btrfs_file_extent_item);
3355                         if (btrfs_file_extent_type(buf, fi) ==
3356                             BTRFS_FILE_EXTENT_INLINE)
3357                                 continue;
3358                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3359                         if (bytenr == 0)
3360                                 continue;
3361
3362                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3363                         key.offset -= btrfs_file_extent_offset(buf, fi);
3364                         ret = process_func(trans, root, bytenr, num_bytes,
3365                                            parent, ref_root, key.objectid,
3366                                            key.offset);
3367                         if (ret)
3368                                 goto fail;
3369                 } else {
3370                         bytenr = btrfs_node_blockptr(buf, i);
3371                         num_bytes = fs_info->nodesize;
3372                         ret = process_func(trans, root, bytenr, num_bytes,
3373                                            parent, ref_root, level - 1, 0);
3374                         if (ret)
3375                                 goto fail;
3376                 }
3377         }
3378         return 0;
3379 fail:
3380         return ret;
3381 }
3382
3383 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3384                   struct extent_buffer *buf, int full_backref)
3385 {
3386         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3387 }
3388
3389 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3390                   struct extent_buffer *buf, int full_backref)
3391 {
3392         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3393 }
3394
3395 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3396                                  struct btrfs_fs_info *fs_info,
3397                                  struct btrfs_path *path,
3398                                  struct btrfs_block_group_cache *cache)
3399 {
3400         int ret;
3401         struct btrfs_root *extent_root = fs_info->extent_root;
3402         unsigned long bi;
3403         struct extent_buffer *leaf;
3404
3405         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3406         if (ret) {
3407                 if (ret > 0)
3408                         ret = -ENOENT;
3409                 goto fail;
3410         }
3411
3412         leaf = path->nodes[0];
3413         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3414         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3415         btrfs_mark_buffer_dirty(leaf);
3416 fail:
3417         btrfs_release_path(path);
3418         return ret;
3419
3420 }
3421
3422 static struct btrfs_block_group_cache *
3423 next_block_group(struct btrfs_fs_info *fs_info,
3424                  struct btrfs_block_group_cache *cache)
3425 {
3426         struct rb_node *node;
3427
3428         spin_lock(&fs_info->block_group_cache_lock);
3429
3430         /* If our block group was removed, we need a full search. */
3431         if (RB_EMPTY_NODE(&cache->cache_node)) {
3432                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3433
3434                 spin_unlock(&fs_info->block_group_cache_lock);
3435                 btrfs_put_block_group(cache);
3436                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3437         }
3438         node = rb_next(&cache->cache_node);
3439         btrfs_put_block_group(cache);
3440         if (node) {
3441                 cache = rb_entry(node, struct btrfs_block_group_cache,
3442                                  cache_node);
3443                 btrfs_get_block_group(cache);
3444         } else
3445                 cache = NULL;
3446         spin_unlock(&fs_info->block_group_cache_lock);
3447         return cache;
3448 }
3449
3450 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3451                             struct btrfs_trans_handle *trans,
3452                             struct btrfs_path *path)
3453 {
3454         struct btrfs_fs_info *fs_info = block_group->fs_info;
3455         struct btrfs_root *root = fs_info->tree_root;
3456         struct inode *inode = NULL;
3457         struct extent_changeset *data_reserved = NULL;
3458         u64 alloc_hint = 0;
3459         int dcs = BTRFS_DC_ERROR;
3460         u64 num_pages = 0;
3461         int retries = 0;
3462         int ret = 0;
3463
3464         /*
3465          * If this block group is smaller than 100 megs don't bother caching the
3466          * block group.
3467          */
3468         if (block_group->key.offset < (100 * SZ_1M)) {
3469                 spin_lock(&block_group->lock);
3470                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3471                 spin_unlock(&block_group->lock);
3472                 return 0;
3473         }
3474
3475         if (trans->aborted)
3476                 return 0;
3477 again:
3478         inode = lookup_free_space_inode(fs_info, block_group, path);
3479         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3480                 ret = PTR_ERR(inode);
3481                 btrfs_release_path(path);
3482                 goto out;
3483         }
3484
3485         if (IS_ERR(inode)) {
3486                 BUG_ON(retries);
3487                 retries++;
3488
3489                 if (block_group->ro)
3490                         goto out_free;
3491
3492                 ret = create_free_space_inode(fs_info, trans, block_group,
3493                                               path);
3494                 if (ret)
3495                         goto out_free;
3496                 goto again;
3497         }
3498
3499         /*
3500          * We want to set the generation to 0, that way if anything goes wrong
3501          * from here on out we know not to trust this cache when we load up next
3502          * time.
3503          */
3504         BTRFS_I(inode)->generation = 0;
3505         ret = btrfs_update_inode(trans, root, inode);
3506         if (ret) {
3507                 /*
3508                  * So theoretically we could recover from this, simply set the
3509                  * super cache generation to 0 so we know to invalidate the
3510                  * cache, but then we'd have to keep track of the block groups
3511                  * that fail this way so we know we _have_ to reset this cache
3512                  * before the next commit or risk reading stale cache.  So to
3513                  * limit our exposure to horrible edge cases lets just abort the
3514                  * transaction, this only happens in really bad situations
3515                  * anyway.
3516                  */
3517                 btrfs_abort_transaction(trans, ret);
3518                 goto out_put;
3519         }
3520         WARN_ON(ret);
3521
3522         /* We've already setup this transaction, go ahead and exit */
3523         if (block_group->cache_generation == trans->transid &&
3524             i_size_read(inode)) {
3525                 dcs = BTRFS_DC_SETUP;
3526                 goto out_put;
3527         }
3528
3529         if (i_size_read(inode) > 0) {
3530                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3531                                         &fs_info->global_block_rsv);
3532                 if (ret)
3533                         goto out_put;
3534
3535                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3536                 if (ret)
3537                         goto out_put;
3538         }
3539
3540         spin_lock(&block_group->lock);
3541         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3542             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3543                 /*
3544                  * don't bother trying to write stuff out _if_
3545                  * a) we're not cached,
3546                  * b) we're with nospace_cache mount option,
3547                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3548                  */
3549                 dcs = BTRFS_DC_WRITTEN;
3550                 spin_unlock(&block_group->lock);
3551                 goto out_put;
3552         }
3553         spin_unlock(&block_group->lock);
3554
3555         /*
3556          * We hit an ENOSPC when setting up the cache in this transaction, just
3557          * skip doing the setup, we've already cleared the cache so we're safe.
3558          */
3559         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3560                 ret = -ENOSPC;
3561                 goto out_put;
3562         }
3563
3564         /*
3565          * Try to preallocate enough space based on how big the block group is.
3566          * Keep in mind this has to include any pinned space which could end up
3567          * taking up quite a bit since it's not folded into the other space
3568          * cache.
3569          */
3570         num_pages = div_u64(block_group->key.offset, SZ_256M);
3571         if (!num_pages)
3572                 num_pages = 1;
3573
3574         num_pages *= 16;
3575         num_pages *= PAGE_SIZE;
3576
3577         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3578         if (ret)
3579                 goto out_put;
3580
3581         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3582                                               num_pages, num_pages,
3583                                               &alloc_hint);
3584         /*
3585          * Our cache requires contiguous chunks so that we don't modify a bunch
3586          * of metadata or split extents when writing the cache out, which means
3587          * we can enospc if we are heavily fragmented in addition to just normal
3588          * out of space conditions.  So if we hit this just skip setting up any
3589          * other block groups for this transaction, maybe we'll unpin enough
3590          * space the next time around.
3591          */
3592         if (!ret)
3593                 dcs = BTRFS_DC_SETUP;
3594         else if (ret == -ENOSPC)
3595                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3596
3597 out_put:
3598         iput(inode);
3599 out_free:
3600         btrfs_release_path(path);
3601 out:
3602         spin_lock(&block_group->lock);
3603         if (!ret && dcs == BTRFS_DC_SETUP)
3604                 block_group->cache_generation = trans->transid;
3605         block_group->disk_cache_state = dcs;
3606         spin_unlock(&block_group->lock);
3607
3608         extent_changeset_free(data_reserved);
3609         return ret;
3610 }
3611
3612 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3613                             struct btrfs_fs_info *fs_info)
3614 {
3615         struct btrfs_block_group_cache *cache, *tmp;
3616         struct btrfs_transaction *cur_trans = trans->transaction;
3617         struct btrfs_path *path;
3618
3619         if (list_empty(&cur_trans->dirty_bgs) ||
3620             !btrfs_test_opt(fs_info, SPACE_CACHE))
3621                 return 0;
3622
3623         path = btrfs_alloc_path();
3624         if (!path)
3625                 return -ENOMEM;
3626
3627         /* Could add new block groups, use _safe just in case */
3628         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3629                                  dirty_list) {
3630                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3631                         cache_save_setup(cache, trans, path);
3632         }
3633
3634         btrfs_free_path(path);
3635         return 0;
3636 }
3637
3638 /*
3639  * transaction commit does final block group cache writeback during a
3640  * critical section where nothing is allowed to change the FS.  This is
3641  * required in order for the cache to actually match the block group,
3642  * but can introduce a lot of latency into the commit.
3643  *
3644  * So, btrfs_start_dirty_block_groups is here to kick off block group
3645  * cache IO.  There's a chance we'll have to redo some of it if the
3646  * block group changes again during the commit, but it greatly reduces
3647  * the commit latency by getting rid of the easy block groups while
3648  * we're still allowing others to join the commit.
3649  */
3650 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3651 {
3652         struct btrfs_fs_info *fs_info = trans->fs_info;
3653         struct btrfs_block_group_cache *cache;
3654         struct btrfs_transaction *cur_trans = trans->transaction;
3655         int ret = 0;
3656         int should_put;
3657         struct btrfs_path *path = NULL;
3658         LIST_HEAD(dirty);
3659         struct list_head *io = &cur_trans->io_bgs;
3660         int num_started = 0;
3661         int loops = 0;
3662
3663         spin_lock(&cur_trans->dirty_bgs_lock);
3664         if (list_empty(&cur_trans->dirty_bgs)) {
3665                 spin_unlock(&cur_trans->dirty_bgs_lock);
3666                 return 0;
3667         }
3668         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3669         spin_unlock(&cur_trans->dirty_bgs_lock);
3670
3671 again:
3672         /*
3673          * make sure all the block groups on our dirty list actually
3674          * exist
3675          */
3676         btrfs_create_pending_block_groups(trans);
3677
3678         if (!path) {
3679                 path = btrfs_alloc_path();
3680                 if (!path)
3681                         return -ENOMEM;
3682         }
3683
3684         /*
3685          * cache_write_mutex is here only to save us from balance or automatic
3686          * removal of empty block groups deleting this block group while we are
3687          * writing out the cache
3688          */
3689         mutex_lock(&trans->transaction->cache_write_mutex);
3690         while (!list_empty(&dirty)) {
3691                 cache = list_first_entry(&dirty,
3692                                          struct btrfs_block_group_cache,
3693                                          dirty_list);
3694                 /*
3695                  * this can happen if something re-dirties a block
3696                  * group that is already under IO.  Just wait for it to
3697                  * finish and then do it all again
3698                  */
3699                 if (!list_empty(&cache->io_list)) {
3700                         list_del_init(&cache->io_list);
3701                         btrfs_wait_cache_io(trans, cache, path);
3702                         btrfs_put_block_group(cache);
3703                 }
3704
3705
3706                 /*
3707                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3708                  * if it should update the cache_state.  Don't delete
3709                  * until after we wait.
3710                  *
3711                  * Since we're not running in the commit critical section
3712                  * we need the dirty_bgs_lock to protect from update_block_group
3713                  */
3714                 spin_lock(&cur_trans->dirty_bgs_lock);
3715                 list_del_init(&cache->dirty_list);
3716                 spin_unlock(&cur_trans->dirty_bgs_lock);
3717
3718                 should_put = 1;
3719
3720                 cache_save_setup(cache, trans, path);
3721
3722                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3723                         cache->io_ctl.inode = NULL;
3724                         ret = btrfs_write_out_cache(fs_info, trans,
3725                                                     cache, path);
3726                         if (ret == 0 && cache->io_ctl.inode) {
3727                                 num_started++;
3728                                 should_put = 0;
3729
3730                                 /*
3731                                  * The cache_write_mutex is protecting the
3732                                  * io_list, also refer to the definition of
3733                                  * btrfs_transaction::io_bgs for more details
3734                                  */
3735                                 list_add_tail(&cache->io_list, io);
3736                         } else {
3737                                 /*
3738                                  * if we failed to write the cache, the
3739                                  * generation will be bad and life goes on
3740                                  */
3741                                 ret = 0;
3742                         }
3743                 }
3744                 if (!ret) {
3745                         ret = write_one_cache_group(trans, fs_info,
3746                                                     path, cache);
3747                         /*
3748                          * Our block group might still be attached to the list
3749                          * of new block groups in the transaction handle of some
3750                          * other task (struct btrfs_trans_handle->new_bgs). This
3751                          * means its block group item isn't yet in the extent
3752                          * tree. If this happens ignore the error, as we will
3753                          * try again later in the critical section of the
3754                          * transaction commit.
3755                          */
3756                         if (ret == -ENOENT) {
3757                                 ret = 0;
3758                                 spin_lock(&cur_trans->dirty_bgs_lock);
3759                                 if (list_empty(&cache->dirty_list)) {
3760                                         list_add_tail(&cache->dirty_list,
3761                                                       &cur_trans->dirty_bgs);
3762                                         btrfs_get_block_group(cache);
3763                                 }
3764                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3765                         } else if (ret) {
3766                                 btrfs_abort_transaction(trans, ret);
3767                         }
3768                 }
3769
3770                 /* if its not on the io list, we need to put the block group */
3771                 if (should_put)
3772                         btrfs_put_block_group(cache);
3773
3774                 if (ret)
3775                         break;
3776
3777                 /*
3778                  * Avoid blocking other tasks for too long. It might even save
3779                  * us from writing caches for block groups that are going to be
3780                  * removed.
3781                  */
3782                 mutex_unlock(&trans->transaction->cache_write_mutex);
3783                 mutex_lock(&trans->transaction->cache_write_mutex);
3784         }
3785         mutex_unlock(&trans->transaction->cache_write_mutex);
3786
3787         /*
3788          * go through delayed refs for all the stuff we've just kicked off
3789          * and then loop back (just once)
3790          */
3791         ret = btrfs_run_delayed_refs(trans, 0);
3792         if (!ret && loops == 0) {
3793                 loops++;
3794                 spin_lock(&cur_trans->dirty_bgs_lock);
3795                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3796                 /*
3797                  * dirty_bgs_lock protects us from concurrent block group
3798                  * deletes too (not just cache_write_mutex).
3799                  */
3800                 if (!list_empty(&dirty)) {
3801                         spin_unlock(&cur_trans->dirty_bgs_lock);
3802                         goto again;
3803                 }
3804                 spin_unlock(&cur_trans->dirty_bgs_lock);
3805         } else if (ret < 0) {
3806                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3807         }
3808
3809         btrfs_free_path(path);
3810         return ret;
3811 }
3812
3813 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3814                                    struct btrfs_fs_info *fs_info)
3815 {
3816         struct btrfs_block_group_cache *cache;
3817         struct btrfs_transaction *cur_trans = trans->transaction;
3818         int ret = 0;
3819         int should_put;
3820         struct btrfs_path *path;
3821         struct list_head *io = &cur_trans->io_bgs;
3822         int num_started = 0;
3823
3824         path = btrfs_alloc_path();
3825         if (!path)
3826                 return -ENOMEM;
3827
3828         /*
3829          * Even though we are in the critical section of the transaction commit,
3830          * we can still have concurrent tasks adding elements to this
3831          * transaction's list of dirty block groups. These tasks correspond to
3832          * endio free space workers started when writeback finishes for a
3833          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3834          * allocate new block groups as a result of COWing nodes of the root
3835          * tree when updating the free space inode. The writeback for the space
3836          * caches is triggered by an earlier call to
3837          * btrfs_start_dirty_block_groups() and iterations of the following
3838          * loop.
3839          * Also we want to do the cache_save_setup first and then run the
3840          * delayed refs to make sure we have the best chance at doing this all
3841          * in one shot.
3842          */
3843         spin_lock(&cur_trans->dirty_bgs_lock);
3844         while (!list_empty(&cur_trans->dirty_bgs)) {
3845                 cache = list_first_entry(&cur_trans->dirty_bgs,
3846                                          struct btrfs_block_group_cache,
3847                                          dirty_list);
3848
3849                 /*
3850                  * this can happen if cache_save_setup re-dirties a block
3851                  * group that is already under IO.  Just wait for it to
3852                  * finish and then do it all again
3853                  */
3854                 if (!list_empty(&cache->io_list)) {
3855                         spin_unlock(&cur_trans->dirty_bgs_lock);
3856                         list_del_init(&cache->io_list);
3857                         btrfs_wait_cache_io(trans, cache, path);
3858                         btrfs_put_block_group(cache);
3859                         spin_lock(&cur_trans->dirty_bgs_lock);
3860                 }
3861
3862                 /*
3863                  * don't remove from the dirty list until after we've waited
3864                  * on any pending IO
3865                  */
3866                 list_del_init(&cache->dirty_list);
3867                 spin_unlock(&cur_trans->dirty_bgs_lock);
3868                 should_put = 1;
3869
3870                 cache_save_setup(cache, trans, path);
3871
3872                 if (!ret)
3873                         ret = btrfs_run_delayed_refs(trans,
3874                                                      (unsigned long) -1);
3875
3876                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3877                         cache->io_ctl.inode = NULL;
3878                         ret = btrfs_write_out_cache(fs_info, trans,
3879                                                     cache, path);
3880                         if (ret == 0 && cache->io_ctl.inode) {
3881                                 num_started++;
3882                                 should_put = 0;
3883                                 list_add_tail(&cache->io_list, io);
3884                         } else {
3885                                 /*
3886                                  * if we failed to write the cache, the
3887                                  * generation will be bad and life goes on
3888                                  */
3889                                 ret = 0;
3890                         }
3891                 }
3892                 if (!ret) {
3893                         ret = write_one_cache_group(trans, fs_info,
3894                                                     path, cache);
3895                         /*
3896                          * One of the free space endio workers might have
3897                          * created a new block group while updating a free space
3898                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3899                          * and hasn't released its transaction handle yet, in
3900                          * which case the new block group is still attached to
3901                          * its transaction handle and its creation has not
3902                          * finished yet (no block group item in the extent tree
3903                          * yet, etc). If this is the case, wait for all free
3904                          * space endio workers to finish and retry. This is a
3905                          * a very rare case so no need for a more efficient and
3906                          * complex approach.
3907                          */
3908                         if (ret == -ENOENT) {
3909                                 wait_event(cur_trans->writer_wait,
3910                                    atomic_read(&cur_trans->num_writers) == 1);
3911                                 ret = write_one_cache_group(trans, fs_info,
3912                                                             path, cache);
3913                         }
3914                         if (ret)
3915                                 btrfs_abort_transaction(trans, ret);
3916                 }
3917
3918                 /* if its not on the io list, we need to put the block group */
3919                 if (should_put)
3920                         btrfs_put_block_group(cache);
3921                 spin_lock(&cur_trans->dirty_bgs_lock);
3922         }
3923         spin_unlock(&cur_trans->dirty_bgs_lock);
3924
3925         /*
3926          * Refer to the definition of io_bgs member for details why it's safe
3927          * to use it without any locking
3928          */
3929         while (!list_empty(io)) {
3930                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3931                                          io_list);
3932                 list_del_init(&cache->io_list);
3933                 btrfs_wait_cache_io(trans, cache, path);
3934                 btrfs_put_block_group(cache);
3935         }
3936
3937         btrfs_free_path(path);
3938         return ret;
3939 }
3940
3941 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3942 {
3943         struct btrfs_block_group_cache *block_group;
3944         int readonly = 0;
3945
3946         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3947         if (!block_group || block_group->ro)
3948                 readonly = 1;
3949         if (block_group)
3950                 btrfs_put_block_group(block_group);
3951         return readonly;
3952 }
3953
3954 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3955 {
3956         struct btrfs_block_group_cache *bg;
3957         bool ret = true;
3958
3959         bg = btrfs_lookup_block_group(fs_info, bytenr);
3960         if (!bg)
3961                 return false;
3962
3963         spin_lock(&bg->lock);
3964         if (bg->ro)
3965                 ret = false;
3966         else
3967                 atomic_inc(&bg->nocow_writers);
3968         spin_unlock(&bg->lock);
3969
3970         /* no put on block group, done by btrfs_dec_nocow_writers */
3971         if (!ret)
3972                 btrfs_put_block_group(bg);
3973
3974         return ret;
3975
3976 }
3977
3978 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3979 {
3980         struct btrfs_block_group_cache *bg;
3981
3982         bg = btrfs_lookup_block_group(fs_info, bytenr);
3983         ASSERT(bg);
3984         if (atomic_dec_and_test(&bg->nocow_writers))
3985                 wake_up_atomic_t(&bg->nocow_writers);
3986         /*
3987          * Once for our lookup and once for the lookup done by a previous call
3988          * to btrfs_inc_nocow_writers()
3989          */
3990         btrfs_put_block_group(bg);
3991         btrfs_put_block_group(bg);
3992 }
3993
3994 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3995 {
3996         wait_on_atomic_t(&bg->nocow_writers, atomic_t_wait,
3997                          TASK_UNINTERRUPTIBLE);
3998 }
3999
4000 static const char *alloc_name(u64 flags)
4001 {
4002         switch (flags) {
4003         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
4004                 return "mixed";
4005         case BTRFS_BLOCK_GROUP_METADATA:
4006                 return "metadata";
4007         case BTRFS_BLOCK_GROUP_DATA:
4008                 return "data";
4009         case BTRFS_BLOCK_GROUP_SYSTEM:
4010                 return "system";
4011         default:
4012                 WARN_ON(1);
4013                 return "invalid-combination";
4014         };
4015 }
4016
4017 static int create_space_info(struct btrfs_fs_info *info, u64 flags,
4018                              struct btrfs_space_info **new)
4019 {
4020
4021         struct btrfs_space_info *space_info;
4022         int i;
4023         int ret;
4024
4025         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
4026         if (!space_info)
4027                 return -ENOMEM;
4028
4029         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
4030                                  GFP_KERNEL);
4031         if (ret) {
4032                 kfree(space_info);
4033                 return ret;
4034         }
4035
4036         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
4037                 INIT_LIST_HEAD(&space_info->block_groups[i]);
4038         init_rwsem(&space_info->groups_sem);
4039         spin_lock_init(&space_info->lock);
4040         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
4041         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4042         init_waitqueue_head(&space_info->wait);
4043         INIT_LIST_HEAD(&space_info->ro_bgs);
4044         INIT_LIST_HEAD(&space_info->tickets);
4045         INIT_LIST_HEAD(&space_info->priority_tickets);
4046
4047         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
4048                                     info->space_info_kobj, "%s",
4049                                     alloc_name(space_info->flags));
4050         if (ret) {
4051                 percpu_counter_destroy(&space_info->total_bytes_pinned);
4052                 kfree(space_info);
4053                 return ret;
4054         }
4055
4056         *new = space_info;
4057         list_add_rcu(&space_info->list, &info->space_info);
4058         if (flags & BTRFS_BLOCK_GROUP_DATA)
4059                 info->data_sinfo = space_info;
4060
4061         return ret;
4062 }
4063
4064 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
4065                              u64 total_bytes, u64 bytes_used,
4066                              u64 bytes_readonly,
4067                              struct btrfs_space_info **space_info)
4068 {
4069         struct btrfs_space_info *found;
4070         int factor;
4071
4072         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
4073                      BTRFS_BLOCK_GROUP_RAID10))
4074                 factor = 2;
4075         else
4076                 factor = 1;
4077
4078         found = __find_space_info(info, flags);
4079         ASSERT(found);
4080         spin_lock(&found->lock);
4081         found->total_bytes += total_bytes;
4082         found->disk_total += total_bytes * factor;
4083         found->bytes_used += bytes_used;
4084         found->disk_used += bytes_used * factor;
4085         found->bytes_readonly += bytes_readonly;
4086         if (total_bytes > 0)
4087                 found->full = 0;
4088         space_info_add_new_bytes(info, found, total_bytes -
4089                                  bytes_used - bytes_readonly);
4090         spin_unlock(&found->lock);
4091         *space_info = found;
4092 }
4093
4094 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4095 {
4096         u64 extra_flags = chunk_to_extended(flags) &
4097                                 BTRFS_EXTENDED_PROFILE_MASK;
4098
4099         write_seqlock(&fs_info->profiles_lock);
4100         if (flags & BTRFS_BLOCK_GROUP_DATA)
4101                 fs_info->avail_data_alloc_bits |= extra_flags;
4102         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4103                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4104         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4105                 fs_info->avail_system_alloc_bits |= extra_flags;
4106         write_sequnlock(&fs_info->profiles_lock);
4107 }
4108
4109 /*
4110  * returns target flags in extended format or 0 if restripe for this
4111  * chunk_type is not in progress
4112  *
4113  * should be called with either volume_mutex or balance_lock held
4114  */
4115 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4116 {
4117         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4118         u64 target = 0;
4119
4120         if (!bctl)
4121                 return 0;
4122
4123         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4124             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4125                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4126         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4127                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4128                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4129         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4130                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4131                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4132         }
4133
4134         return target;
4135 }
4136
4137 /*
4138  * @flags: available profiles in extended format (see ctree.h)
4139  *
4140  * Returns reduced profile in chunk format.  If profile changing is in
4141  * progress (either running or paused) picks the target profile (if it's
4142  * already available), otherwise falls back to plain reducing.
4143  */
4144 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4145 {
4146         u64 num_devices = fs_info->fs_devices->rw_devices;
4147         u64 target;
4148         u64 raid_type;
4149         u64 allowed = 0;
4150
4151         /*
4152          * see if restripe for this chunk_type is in progress, if so
4153          * try to reduce to the target profile
4154          */
4155         spin_lock(&fs_info->balance_lock);
4156         target = get_restripe_target(fs_info, flags);
4157         if (target) {
4158                 /* pick target profile only if it's already available */
4159                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4160                         spin_unlock(&fs_info->balance_lock);
4161                         return extended_to_chunk(target);
4162                 }
4163         }
4164         spin_unlock(&fs_info->balance_lock);
4165
4166         /* First, mask out the RAID levels which aren't possible */
4167         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4168                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4169                         allowed |= btrfs_raid_group[raid_type];
4170         }
4171         allowed &= flags;
4172
4173         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4174                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4175         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4176                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4177         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4178                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4179         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4180                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4181         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4182                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4183
4184         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4185
4186         return extended_to_chunk(flags | allowed);
4187 }
4188
4189 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4190 {
4191         unsigned seq;
4192         u64 flags;
4193
4194         do {
4195                 flags = orig_flags;
4196                 seq = read_seqbegin(&fs_info->profiles_lock);
4197
4198                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4199                         flags |= fs_info->avail_data_alloc_bits;
4200                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4201                         flags |= fs_info->avail_system_alloc_bits;
4202                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4203                         flags |= fs_info->avail_metadata_alloc_bits;
4204         } while (read_seqretry(&fs_info->profiles_lock, seq));
4205
4206         return btrfs_reduce_alloc_profile(fs_info, flags);
4207 }
4208
4209 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4210 {
4211         struct btrfs_fs_info *fs_info = root->fs_info;
4212         u64 flags;
4213         u64 ret;
4214
4215         if (data)
4216                 flags = BTRFS_BLOCK_GROUP_DATA;
4217         else if (root == fs_info->chunk_root)
4218                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4219         else
4220                 flags = BTRFS_BLOCK_GROUP_METADATA;
4221
4222         ret = get_alloc_profile(fs_info, flags);
4223         return ret;
4224 }
4225
4226 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4227 {
4228         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4229 }
4230
4231 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4232 {
4233         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4234 }
4235
4236 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4237 {
4238         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4239 }
4240
4241 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4242                                  bool may_use_included)
4243 {
4244         ASSERT(s_info);
4245         return s_info->bytes_used + s_info->bytes_reserved +
4246                 s_info->bytes_pinned + s_info->bytes_readonly +
4247                 (may_use_included ? s_info->bytes_may_use : 0);
4248 }
4249
4250 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4251 {
4252         struct btrfs_root *root = inode->root;
4253         struct btrfs_fs_info *fs_info = root->fs_info;
4254         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4255         u64 used;
4256         int ret = 0;
4257         int need_commit = 2;
4258         int have_pinned_space;
4259
4260         /* make sure bytes are sectorsize aligned */
4261         bytes = ALIGN(bytes, fs_info->sectorsize);
4262
4263         if (btrfs_is_free_space_inode(inode)) {
4264                 need_commit = 0;
4265                 ASSERT(current->journal_info);
4266         }
4267
4268 again:
4269         /* make sure we have enough space to handle the data first */
4270         spin_lock(&data_sinfo->lock);
4271         used = btrfs_space_info_used(data_sinfo, true);
4272
4273         if (used + bytes > data_sinfo->total_bytes) {
4274                 struct btrfs_trans_handle *trans;
4275
4276                 /*
4277                  * if we don't have enough free bytes in this space then we need
4278                  * to alloc a new chunk.
4279                  */
4280                 if (!data_sinfo->full) {
4281                         u64 alloc_target;
4282
4283                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4284                         spin_unlock(&data_sinfo->lock);
4285
4286                         alloc_target = btrfs_data_alloc_profile(fs_info);
4287                         /*
4288                          * It is ugly that we don't call nolock join
4289                          * transaction for the free space inode case here.
4290                          * But it is safe because we only do the data space
4291                          * reservation for the free space cache in the
4292                          * transaction context, the common join transaction
4293                          * just increase the counter of the current transaction
4294                          * handler, doesn't try to acquire the trans_lock of
4295                          * the fs.
4296                          */
4297                         trans = btrfs_join_transaction(root);
4298                         if (IS_ERR(trans))
4299                                 return PTR_ERR(trans);
4300
4301                         ret = do_chunk_alloc(trans, fs_info, alloc_target,
4302                                              CHUNK_ALLOC_NO_FORCE);
4303                         btrfs_end_transaction(trans);
4304                         if (ret < 0) {
4305                                 if (ret != -ENOSPC)
4306                                         return ret;
4307                                 else {
4308                                         have_pinned_space = 1;
4309                                         goto commit_trans;
4310                                 }
4311                         }
4312
4313                         goto again;
4314                 }
4315
4316                 /*
4317                  * If we don't have enough pinned space to deal with this
4318                  * allocation, and no removed chunk in current transaction,
4319                  * don't bother committing the transaction.
4320                  */
4321                 have_pinned_space = percpu_counter_compare(
4322                         &data_sinfo->total_bytes_pinned,
4323                         used + bytes - data_sinfo->total_bytes);
4324                 spin_unlock(&data_sinfo->lock);
4325
4326                 /* commit the current transaction and try again */
4327 commit_trans:
4328                 if (need_commit) {
4329                         need_commit--;
4330
4331                         if (need_commit > 0) {
4332                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4333                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4334                                                          (u64)-1);
4335                         }
4336
4337                         trans = btrfs_join_transaction(root);
4338                         if (IS_ERR(trans))
4339                                 return PTR_ERR(trans);
4340                         if (have_pinned_space >= 0 ||
4341                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4342                                      &trans->transaction->flags) ||
4343                             need_commit > 0) {
4344                                 ret = btrfs_commit_transaction(trans);
4345                                 if (ret)
4346                                         return ret;
4347                                 /*
4348                                  * The cleaner kthread might still be doing iput
4349                                  * operations. Wait for it to finish so that
4350                                  * more space is released.
4351                                  */
4352                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4353                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4354                                 goto again;
4355                         } else {
4356                                 btrfs_end_transaction(trans);
4357                         }
4358                 }
4359
4360                 trace_btrfs_space_reservation(fs_info,
4361                                               "space_info:enospc",
4362                                               data_sinfo->flags, bytes, 1);
4363                 return -ENOSPC;
4364         }
4365         data_sinfo->bytes_may_use += bytes;
4366         trace_btrfs_space_reservation(fs_info, "space_info",
4367                                       data_sinfo->flags, bytes, 1);
4368         spin_unlock(&data_sinfo->lock);
4369
4370         return ret;
4371 }
4372
4373 int btrfs_check_data_free_space(struct inode *inode,
4374                         struct extent_changeset **reserved, u64 start, u64 len)
4375 {
4376         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4377         int ret;
4378
4379         /* align the range */
4380         len = round_up(start + len, fs_info->sectorsize) -
4381               round_down(start, fs_info->sectorsize);
4382         start = round_down(start, fs_info->sectorsize);
4383
4384         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4385         if (ret < 0)
4386                 return ret;
4387
4388         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4389         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4390         if (ret < 0)
4391                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4392         else
4393                 ret = 0;
4394         return ret;
4395 }
4396
4397 /*
4398  * Called if we need to clear a data reservation for this inode
4399  * Normally in a error case.
4400  *
4401  * This one will *NOT* use accurate qgroup reserved space API, just for case
4402  * which we can't sleep and is sure it won't affect qgroup reserved space.
4403  * Like clear_bit_hook().
4404  */
4405 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4406                                             u64 len)
4407 {
4408         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4409         struct btrfs_space_info *data_sinfo;
4410
4411         /* Make sure the range is aligned to sectorsize */
4412         len = round_up(start + len, fs_info->sectorsize) -
4413               round_down(start, fs_info->sectorsize);
4414         start = round_down(start, fs_info->sectorsize);
4415
4416         data_sinfo = fs_info->data_sinfo;
4417         spin_lock(&data_sinfo->lock);
4418         if (WARN_ON(data_sinfo->bytes_may_use < len))
4419                 data_sinfo->bytes_may_use = 0;
4420         else
4421                 data_sinfo->bytes_may_use -= len;
4422         trace_btrfs_space_reservation(fs_info, "space_info",
4423                                       data_sinfo->flags, len, 0);
4424         spin_unlock(&data_sinfo->lock);
4425 }
4426
4427 /*
4428  * Called if we need to clear a data reservation for this inode
4429  * Normally in a error case.
4430  *
4431  * This one will handle the per-inode data rsv map for accurate reserved
4432  * space framework.
4433  */
4434 void btrfs_free_reserved_data_space(struct inode *inode,
4435                         struct extent_changeset *reserved, u64 start, u64 len)
4436 {
4437         struct btrfs_root *root = BTRFS_I(inode)->root;
4438
4439         /* Make sure the range is aligned to sectorsize */
4440         len = round_up(start + len, root->fs_info->sectorsize) -
4441               round_down(start, root->fs_info->sectorsize);
4442         start = round_down(start, root->fs_info->sectorsize);
4443
4444         btrfs_free_reserved_data_space_noquota(inode, start, len);
4445         btrfs_qgroup_free_data(inode, reserved, start, len);
4446 }
4447
4448 static void force_metadata_allocation(struct btrfs_fs_info *info)
4449 {
4450         struct list_head *head = &info->space_info;
4451         struct btrfs_space_info *found;
4452
4453         rcu_read_lock();
4454         list_for_each_entry_rcu(found, head, list) {
4455                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4456                         found->force_alloc = CHUNK_ALLOC_FORCE;
4457         }
4458         rcu_read_unlock();
4459 }
4460
4461 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4462 {
4463         return (global->size << 1);
4464 }
4465
4466 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4467                               struct btrfs_space_info *sinfo, int force)
4468 {
4469         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4470         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4471         u64 thresh;
4472
4473         if (force == CHUNK_ALLOC_FORCE)
4474                 return 1;
4475
4476         /*
4477          * We need to take into account the global rsv because for all intents
4478          * and purposes it's used space.  Don't worry about locking the
4479          * global_rsv, it doesn't change except when the transaction commits.
4480          */
4481         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4482                 bytes_used += calc_global_rsv_need_space(global_rsv);
4483
4484         /*
4485          * in limited mode, we want to have some free space up to
4486          * about 1% of the FS size.
4487          */
4488         if (force == CHUNK_ALLOC_LIMITED) {
4489                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4490                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4491
4492                 if (sinfo->total_bytes - bytes_used < thresh)
4493                         return 1;
4494         }
4495
4496         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4497                 return 0;
4498         return 1;
4499 }
4500
4501 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4502 {
4503         u64 num_dev;
4504
4505         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4506                     BTRFS_BLOCK_GROUP_RAID0 |
4507                     BTRFS_BLOCK_GROUP_RAID5 |
4508                     BTRFS_BLOCK_GROUP_RAID6))
4509                 num_dev = fs_info->fs_devices->rw_devices;
4510         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4511                 num_dev = 2;
4512         else
4513                 num_dev = 1;    /* DUP or single */
4514
4515         return num_dev;
4516 }
4517
4518 /*
4519  * If @is_allocation is true, reserve space in the system space info necessary
4520  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4521  * removing a chunk.
4522  */
4523 void check_system_chunk(struct btrfs_trans_handle *trans,
4524                         struct btrfs_fs_info *fs_info, u64 type)
4525 {
4526         struct btrfs_space_info *info;
4527         u64 left;
4528         u64 thresh;
4529         int ret = 0;
4530         u64 num_devs;
4531
4532         /*
4533          * Needed because we can end up allocating a system chunk and for an
4534          * atomic and race free space reservation in the chunk block reserve.
4535          */
4536         lockdep_assert_held(&fs_info->chunk_mutex);
4537
4538         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4539         spin_lock(&info->lock);
4540         left = info->total_bytes - btrfs_space_info_used(info, true);
4541         spin_unlock(&info->lock);
4542
4543         num_devs = get_profile_num_devs(fs_info, type);
4544
4545         /* num_devs device items to update and 1 chunk item to add or remove */
4546         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4547                 btrfs_calc_trans_metadata_size(fs_info, 1);
4548
4549         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4550                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4551                            left, thresh, type);
4552                 dump_space_info(fs_info, info, 0, 0);
4553         }
4554
4555         if (left < thresh) {
4556                 u64 flags = btrfs_system_alloc_profile(fs_info);
4557
4558                 /*
4559                  * Ignore failure to create system chunk. We might end up not
4560                  * needing it, as we might not need to COW all nodes/leafs from
4561                  * the paths we visit in the chunk tree (they were already COWed
4562                  * or created in the current transaction for example).
4563                  */
4564                 ret = btrfs_alloc_chunk(trans, fs_info, flags);
4565         }
4566
4567         if (!ret) {
4568                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4569                                           &fs_info->chunk_block_rsv,
4570                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4571                 if (!ret)
4572                         trans->chunk_bytes_reserved += thresh;
4573         }
4574 }
4575
4576 /*
4577  * If force is CHUNK_ALLOC_FORCE:
4578  *    - return 1 if it successfully allocates a chunk,
4579  *    - return errors including -ENOSPC otherwise.
4580  * If force is NOT CHUNK_ALLOC_FORCE:
4581  *    - return 0 if it doesn't need to allocate a new chunk,
4582  *    - return 1 if it successfully allocates a chunk,
4583  *    - return errors including -ENOSPC otherwise.
4584  */
4585 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4586                           struct btrfs_fs_info *fs_info, u64 flags, int force)
4587 {
4588         struct btrfs_space_info *space_info;
4589         int wait_for_alloc = 0;
4590         int ret = 0;
4591
4592         /* Don't re-enter if we're already allocating a chunk */
4593         if (trans->allocating_chunk)
4594                 return -ENOSPC;
4595
4596         space_info = __find_space_info(fs_info, flags);
4597         ASSERT(space_info);
4598
4599 again:
4600         spin_lock(&space_info->lock);
4601         if (force < space_info->force_alloc)
4602                 force = space_info->force_alloc;
4603         if (space_info->full) {
4604                 if (should_alloc_chunk(fs_info, space_info, force))
4605                         ret = -ENOSPC;
4606                 else
4607                         ret = 0;
4608                 spin_unlock(&space_info->lock);
4609                 return ret;
4610         }
4611
4612         if (!should_alloc_chunk(fs_info, space_info, force)) {
4613                 spin_unlock(&space_info->lock);
4614                 return 0;
4615         } else if (space_info->chunk_alloc) {
4616                 wait_for_alloc = 1;
4617         } else {
4618                 space_info->chunk_alloc = 1;
4619         }
4620
4621         spin_unlock(&space_info->lock);
4622
4623         mutex_lock(&fs_info->chunk_mutex);
4624
4625         /*
4626          * The chunk_mutex is held throughout the entirety of a chunk
4627          * allocation, so once we've acquired the chunk_mutex we know that the
4628          * other guy is done and we need to recheck and see if we should
4629          * allocate.
4630          */
4631         if (wait_for_alloc) {
4632                 mutex_unlock(&fs_info->chunk_mutex);
4633                 wait_for_alloc = 0;
4634                 cond_resched();
4635                 goto again;
4636         }
4637
4638         trans->allocating_chunk = true;
4639
4640         /*
4641          * If we have mixed data/metadata chunks we want to make sure we keep
4642          * allocating mixed chunks instead of individual chunks.
4643          */
4644         if (btrfs_mixed_space_info(space_info))
4645                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4646
4647         /*
4648          * if we're doing a data chunk, go ahead and make sure that
4649          * we keep a reasonable number of metadata chunks allocated in the
4650          * FS as well.
4651          */
4652         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4653                 fs_info->data_chunk_allocations++;
4654                 if (!(fs_info->data_chunk_allocations %
4655                       fs_info->metadata_ratio))
4656                         force_metadata_allocation(fs_info);
4657         }
4658
4659         /*
4660          * Check if we have enough space in SYSTEM chunk because we may need
4661          * to update devices.
4662          */
4663         check_system_chunk(trans, fs_info, flags);
4664
4665         ret = btrfs_alloc_chunk(trans, fs_info, flags);
4666         trans->allocating_chunk = false;
4667
4668         spin_lock(&space_info->lock);
4669         if (ret < 0 && ret != -ENOSPC)
4670                 goto out;
4671         if (ret)
4672                 space_info->full = 1;
4673         else
4674                 ret = 1;
4675
4676         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4677 out:
4678         space_info->chunk_alloc = 0;
4679         spin_unlock(&space_info->lock);
4680         mutex_unlock(&fs_info->chunk_mutex);
4681         /*
4682          * When we allocate a new chunk we reserve space in the chunk block
4683          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4684          * add new nodes/leafs to it if we end up needing to do it when
4685          * inserting the chunk item and updating device items as part of the
4686          * second phase of chunk allocation, performed by
4687          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4688          * large number of new block groups to create in our transaction
4689          * handle's new_bgs list to avoid exhausting the chunk block reserve
4690          * in extreme cases - like having a single transaction create many new
4691          * block groups when starting to write out the free space caches of all
4692          * the block groups that were made dirty during the lifetime of the
4693          * transaction.
4694          */
4695         if (trans->can_flush_pending_bgs &&
4696             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4697                 btrfs_create_pending_block_groups(trans);
4698                 btrfs_trans_release_chunk_metadata(trans);
4699         }
4700         return ret;
4701 }
4702
4703 static int can_overcommit(struct btrfs_fs_info *fs_info,
4704                           struct btrfs_space_info *space_info, u64 bytes,
4705                           enum btrfs_reserve_flush_enum flush,
4706                           bool system_chunk)
4707 {
4708         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4709         u64 profile;
4710         u64 space_size;
4711         u64 avail;
4712         u64 used;
4713
4714         /* Don't overcommit when in mixed mode. */
4715         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4716                 return 0;
4717
4718         if (system_chunk)
4719                 profile = btrfs_system_alloc_profile(fs_info);
4720         else
4721                 profile = btrfs_metadata_alloc_profile(fs_info);
4722
4723         used = btrfs_space_info_used(space_info, false);
4724
4725         /*
4726          * We only want to allow over committing if we have lots of actual space
4727          * free, but if we don't have enough space to handle the global reserve
4728          * space then we could end up having a real enospc problem when trying
4729          * to allocate a chunk or some other such important allocation.
4730          */
4731         spin_lock(&global_rsv->lock);
4732         space_size = calc_global_rsv_need_space(global_rsv);
4733         spin_unlock(&global_rsv->lock);
4734         if (used + space_size >= space_info->total_bytes)
4735                 return 0;
4736
4737         used += space_info->bytes_may_use;
4738
4739         avail = atomic64_read(&fs_info->free_chunk_space);
4740
4741         /*
4742          * If we have dup, raid1 or raid10 then only half of the free
4743          * space is actually useable.  For raid56, the space info used
4744          * doesn't include the parity drive, so we don't have to
4745          * change the math
4746          */
4747         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4748                        BTRFS_BLOCK_GROUP_RAID1 |
4749                        BTRFS_BLOCK_GROUP_RAID10))
4750                 avail >>= 1;
4751
4752         /*
4753          * If we aren't flushing all things, let us overcommit up to
4754          * 1/2th of the space. If we can flush, don't let us overcommit
4755          * too much, let it overcommit up to 1/8 of the space.
4756          */
4757         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4758                 avail >>= 3;
4759         else
4760                 avail >>= 1;
4761
4762         if (used + bytes < space_info->total_bytes + avail)
4763                 return 1;
4764         return 0;
4765 }
4766
4767 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4768                                          unsigned long nr_pages, int nr_items)
4769 {
4770         struct super_block *sb = fs_info->sb;
4771
4772         if (down_read_trylock(&sb->s_umount)) {
4773                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4774                 up_read(&sb->s_umount);
4775         } else {
4776                 /*
4777                  * We needn't worry the filesystem going from r/w to r/o though
4778                  * we don't acquire ->s_umount mutex, because the filesystem
4779                  * should guarantee the delalloc inodes list be empty after
4780                  * the filesystem is readonly(all dirty pages are written to
4781                  * the disk).
4782                  */
4783                 btrfs_start_delalloc_roots(fs_info, 0, nr_items);
4784                 if (!current->journal_info)
4785                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4786         }
4787 }
4788
4789 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4790                                         u64 to_reclaim)
4791 {
4792         u64 bytes;
4793         u64 nr;
4794
4795         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4796         nr = div64_u64(to_reclaim, bytes);
4797         if (!nr)
4798                 nr = 1;
4799         return nr;
4800 }
4801
4802 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4803
4804 /*
4805  * shrink metadata reservation for delalloc
4806  */
4807 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4808                             u64 orig, bool wait_ordered)
4809 {
4810         struct btrfs_space_info *space_info;
4811         struct btrfs_trans_handle *trans;
4812         u64 delalloc_bytes;
4813         u64 max_reclaim;
4814         u64 items;
4815         long time_left;
4816         unsigned long nr_pages;
4817         int loops;
4818
4819         /* Calc the number of the pages we need flush for space reservation */
4820         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4821         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4822
4823         trans = (struct btrfs_trans_handle *)current->journal_info;
4824         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4825
4826         delalloc_bytes = percpu_counter_sum_positive(
4827                                                 &fs_info->delalloc_bytes);
4828         if (delalloc_bytes == 0) {
4829                 if (trans)
4830                         return;
4831                 if (wait_ordered)
4832                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4833                 return;
4834         }
4835
4836         loops = 0;
4837         while (delalloc_bytes && loops < 3) {
4838                 max_reclaim = min(delalloc_bytes, to_reclaim);
4839                 nr_pages = max_reclaim >> PAGE_SHIFT;
4840                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4841                 /*
4842                  * We need to wait for the async pages to actually start before
4843                  * we do anything.
4844                  */
4845                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4846                 if (!max_reclaim)
4847                         goto skip_async;
4848
4849                 if (max_reclaim <= nr_pages)
4850                         max_reclaim = 0;
4851                 else
4852                         max_reclaim -= nr_pages;
4853
4854                 wait_event(fs_info->async_submit_wait,
4855                            atomic_read(&fs_info->async_delalloc_pages) <=
4856                            (int)max_reclaim);
4857 skip_async:
4858                 spin_lock(&space_info->lock);
4859                 if (list_empty(&space_info->tickets) &&
4860                     list_empty(&space_info->priority_tickets)) {
4861                         spin_unlock(&space_info->lock);
4862                         break;
4863                 }
4864                 spin_unlock(&space_info->lock);
4865
4866                 loops++;
4867                 if (wait_ordered && !trans) {
4868                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4869                 } else {
4870                         time_left = schedule_timeout_killable(1);
4871                         if (time_left)
4872                                 break;
4873                 }
4874                 delalloc_bytes = percpu_counter_sum_positive(
4875                                                 &fs_info->delalloc_bytes);
4876         }
4877 }
4878
4879 struct reserve_ticket {
4880         u64 bytes;
4881         int error;
4882         struct list_head list;
4883         wait_queue_head_t wait;
4884 };
4885
4886 /**
4887  * maybe_commit_transaction - possibly commit the transaction if its ok to
4888  * @root - the root we're allocating for
4889  * @bytes - the number of bytes we want to reserve
4890  * @force - force the commit
4891  *
4892  * This will check to make sure that committing the transaction will actually
4893  * get us somewhere and then commit the transaction if it does.  Otherwise it
4894  * will return -ENOSPC.
4895  */
4896 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4897                                   struct btrfs_space_info *space_info)
4898 {
4899         struct reserve_ticket *ticket = NULL;
4900         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4901         struct btrfs_trans_handle *trans;
4902         u64 bytes;
4903
4904         trans = (struct btrfs_trans_handle *)current->journal_info;
4905         if (trans)
4906                 return -EAGAIN;
4907
4908         spin_lock(&space_info->lock);
4909         if (!list_empty(&space_info->priority_tickets))
4910                 ticket = list_first_entry(&space_info->priority_tickets,
4911                                           struct reserve_ticket, list);
4912         else if (!list_empty(&space_info->tickets))
4913                 ticket = list_first_entry(&space_info->tickets,
4914                                           struct reserve_ticket, list);
4915         bytes = (ticket) ? ticket->bytes : 0;
4916         spin_unlock(&space_info->lock);
4917
4918         if (!bytes)
4919                 return 0;
4920
4921         /* See if there is enough pinned space to make this reservation */
4922         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4923                                    bytes) >= 0)
4924                 goto commit;
4925
4926         /*
4927          * See if there is some space in the delayed insertion reservation for
4928          * this reservation.
4929          */
4930         if (space_info != delayed_rsv->space_info)
4931                 return -ENOSPC;
4932
4933         spin_lock(&delayed_rsv->lock);
4934         if (delayed_rsv->size > bytes)
4935                 bytes = 0;
4936         else
4937                 bytes -= delayed_rsv->size;
4938         spin_unlock(&delayed_rsv->lock);
4939
4940         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4941                                    bytes) < 0) {
4942                 return -ENOSPC;
4943         }
4944
4945 commit:
4946         trans = btrfs_join_transaction(fs_info->extent_root);
4947         if (IS_ERR(trans))
4948                 return -ENOSPC;
4949
4950         return btrfs_commit_transaction(trans);
4951 }
4952
4953 /*
4954  * Try to flush some data based on policy set by @state. This is only advisory
4955  * and may fail for various reasons. The caller is supposed to examine the
4956  * state of @space_info to detect the outcome.
4957  */
4958 static void flush_space(struct btrfs_fs_info *fs_info,
4959                        struct btrfs_space_info *space_info, u64 num_bytes,
4960                        int state)
4961 {
4962         struct btrfs_root *root = fs_info->extent_root;
4963         struct btrfs_trans_handle *trans;
4964         int nr;
4965         int ret = 0;
4966
4967         switch (state) {
4968         case FLUSH_DELAYED_ITEMS_NR:
4969         case FLUSH_DELAYED_ITEMS:
4970                 if (state == FLUSH_DELAYED_ITEMS_NR)
4971                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4972                 else
4973                         nr = -1;
4974
4975                 trans = btrfs_join_transaction(root);
4976                 if (IS_ERR(trans)) {
4977                         ret = PTR_ERR(trans);
4978                         break;
4979                 }
4980                 ret = btrfs_run_delayed_items_nr(trans, nr);
4981                 btrfs_end_transaction(trans);
4982                 break;
4983         case FLUSH_DELALLOC:
4984         case FLUSH_DELALLOC_WAIT:
4985                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4986                                 state == FLUSH_DELALLOC_WAIT);
4987                 break;
4988         case ALLOC_CHUNK:
4989                 trans = btrfs_join_transaction(root);
4990                 if (IS_ERR(trans)) {
4991                         ret = PTR_ERR(trans);
4992                         break;
4993                 }
4994                 ret = do_chunk_alloc(trans, fs_info,
4995                                      btrfs_metadata_alloc_profile(fs_info),
4996                                      CHUNK_ALLOC_NO_FORCE);
4997                 btrfs_end_transaction(trans);
4998                 if (ret > 0 || ret == -ENOSPC)
4999                         ret = 0;
5000                 break;
5001         case COMMIT_TRANS:
5002                 ret = may_commit_transaction(fs_info, space_info);
5003                 break;
5004         default:
5005                 ret = -ENOSPC;
5006                 break;
5007         }
5008
5009         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
5010                                 ret);
5011         return;
5012 }
5013
5014 static inline u64
5015 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
5016                                  struct btrfs_space_info *space_info,
5017                                  bool system_chunk)
5018 {
5019         struct reserve_ticket *ticket;
5020         u64 used;
5021         u64 expected;
5022         u64 to_reclaim = 0;
5023
5024         list_for_each_entry(ticket, &space_info->tickets, list)
5025                 to_reclaim += ticket->bytes;
5026         list_for_each_entry(ticket, &space_info->priority_tickets, list)
5027                 to_reclaim += ticket->bytes;
5028         if (to_reclaim)
5029                 return to_reclaim;
5030
5031         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
5032         if (can_overcommit(fs_info, space_info, to_reclaim,
5033                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5034                 return 0;
5035
5036         used = btrfs_space_info_used(space_info, true);
5037
5038         if (can_overcommit(fs_info, space_info, SZ_1M,
5039                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5040                 expected = div_factor_fine(space_info->total_bytes, 95);
5041         else
5042                 expected = div_factor_fine(space_info->total_bytes, 90);
5043
5044         if (used > expected)
5045                 to_reclaim = used - expected;
5046         else
5047                 to_reclaim = 0;
5048         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
5049                                      space_info->bytes_reserved);
5050         return to_reclaim;
5051 }
5052
5053 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
5054                                         struct btrfs_space_info *space_info,
5055                                         u64 used, bool system_chunk)
5056 {
5057         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
5058
5059         /* If we're just plain full then async reclaim just slows us down. */
5060         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
5061                 return 0;
5062
5063         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5064                                               system_chunk))
5065                 return 0;
5066
5067         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
5068                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
5069 }
5070
5071 static void wake_all_tickets(struct list_head *head)
5072 {
5073         struct reserve_ticket *ticket;
5074
5075         while (!list_empty(head)) {
5076                 ticket = list_first_entry(head, struct reserve_ticket, list);
5077                 list_del_init(&ticket->list);
5078                 ticket->error = -ENOSPC;
5079                 wake_up(&ticket->wait);
5080         }
5081 }
5082
5083 /*
5084  * This is for normal flushers, we can wait all goddamned day if we want to.  We
5085  * will loop and continuously try to flush as long as we are making progress.
5086  * We count progress as clearing off tickets each time we have to loop.
5087  */
5088 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
5089 {
5090         struct btrfs_fs_info *fs_info;
5091         struct btrfs_space_info *space_info;
5092         u64 to_reclaim;
5093         int flush_state;
5094         int commit_cycles = 0;
5095         u64 last_tickets_id;
5096
5097         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5098         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5099
5100         spin_lock(&space_info->lock);
5101         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5102                                                       false);
5103         if (!to_reclaim) {
5104                 space_info->flush = 0;
5105                 spin_unlock(&space_info->lock);
5106                 return;
5107         }
5108         last_tickets_id = space_info->tickets_id;
5109         spin_unlock(&space_info->lock);
5110
5111         flush_state = FLUSH_DELAYED_ITEMS_NR;
5112         do {
5113                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5114                 spin_lock(&space_info->lock);
5115                 if (list_empty(&space_info->tickets)) {
5116                         space_info->flush = 0;
5117                         spin_unlock(&space_info->lock);
5118                         return;
5119                 }
5120                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5121                                                               space_info,
5122                                                               false);
5123                 if (last_tickets_id == space_info->tickets_id) {
5124                         flush_state++;
5125                 } else {
5126                         last_tickets_id = space_info->tickets_id;
5127                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5128                         if (commit_cycles)
5129                                 commit_cycles--;
5130                 }
5131
5132                 if (flush_state > COMMIT_TRANS) {
5133                         commit_cycles++;
5134                         if (commit_cycles > 2) {
5135                                 wake_all_tickets(&space_info->tickets);
5136                                 space_info->flush = 0;
5137                         } else {
5138                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5139                         }
5140                 }
5141                 spin_unlock(&space_info->lock);
5142         } while (flush_state <= COMMIT_TRANS);
5143 }
5144
5145 void btrfs_init_async_reclaim_work(struct work_struct *work)
5146 {
5147         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5148 }
5149
5150 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5151                                             struct btrfs_space_info *space_info,
5152                                             struct reserve_ticket *ticket)
5153 {
5154         u64 to_reclaim;
5155         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5156
5157         spin_lock(&space_info->lock);
5158         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5159                                                       false);
5160         if (!to_reclaim) {
5161                 spin_unlock(&space_info->lock);
5162                 return;
5163         }
5164         spin_unlock(&space_info->lock);
5165
5166         do {
5167                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5168                 flush_state++;
5169                 spin_lock(&space_info->lock);
5170                 if (ticket->bytes == 0) {
5171                         spin_unlock(&space_info->lock);
5172                         return;
5173                 }
5174                 spin_unlock(&space_info->lock);
5175
5176                 /*
5177                  * Priority flushers can't wait on delalloc without
5178                  * deadlocking.
5179                  */
5180                 if (flush_state == FLUSH_DELALLOC ||
5181                     flush_state == FLUSH_DELALLOC_WAIT)
5182                         flush_state = ALLOC_CHUNK;
5183         } while (flush_state < COMMIT_TRANS);
5184 }
5185
5186 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5187                                struct btrfs_space_info *space_info,
5188                                struct reserve_ticket *ticket, u64 orig_bytes)
5189
5190 {
5191         DEFINE_WAIT(wait);
5192         int ret = 0;
5193
5194         spin_lock(&space_info->lock);
5195         while (ticket->bytes > 0 && ticket->error == 0) {
5196                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5197                 if (ret) {
5198                         ret = -EINTR;
5199                         break;
5200                 }
5201                 spin_unlock(&space_info->lock);
5202
5203                 schedule();
5204
5205                 finish_wait(&ticket->wait, &wait);
5206                 spin_lock(&space_info->lock);
5207         }
5208         if (!ret)
5209                 ret = ticket->error;
5210         if (!list_empty(&ticket->list))
5211                 list_del_init(&ticket->list);
5212         if (ticket->bytes && ticket->bytes < orig_bytes) {
5213                 u64 num_bytes = orig_bytes - ticket->bytes;
5214                 space_info->bytes_may_use -= num_bytes;
5215                 trace_btrfs_space_reservation(fs_info, "space_info",
5216                                               space_info->flags, num_bytes, 0);
5217         }
5218         spin_unlock(&space_info->lock);
5219
5220         return ret;
5221 }
5222
5223 /**
5224  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5225  * @root - the root we're allocating for
5226  * @space_info - the space info we want to allocate from
5227  * @orig_bytes - the number of bytes we want
5228  * @flush - whether or not we can flush to make our reservation
5229  *
5230  * This will reserve orig_bytes number of bytes from the space info associated
5231  * with the block_rsv.  If there is not enough space it will make an attempt to
5232  * flush out space to make room.  It will do this by flushing delalloc if
5233  * possible or committing the transaction.  If flush is 0 then no attempts to
5234  * regain reservations will be made and this will fail if there is not enough
5235  * space already.
5236  */
5237 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5238                                     struct btrfs_space_info *space_info,
5239                                     u64 orig_bytes,
5240                                     enum btrfs_reserve_flush_enum flush,
5241                                     bool system_chunk)
5242 {
5243         struct reserve_ticket ticket;
5244         u64 used;
5245         int ret = 0;
5246
5247         ASSERT(orig_bytes);
5248         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5249
5250         spin_lock(&space_info->lock);
5251         ret = -ENOSPC;
5252         used = btrfs_space_info_used(space_info, true);
5253
5254         /*
5255          * If we have enough space then hooray, make our reservation and carry
5256          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5257          * If not things get more complicated.
5258          */
5259         if (used + orig_bytes <= space_info->total_bytes) {
5260                 space_info->bytes_may_use += orig_bytes;
5261                 trace_btrfs_space_reservation(fs_info, "space_info",
5262                                               space_info->flags, orig_bytes, 1);
5263                 ret = 0;
5264         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5265                                   system_chunk)) {
5266                 space_info->bytes_may_use += orig_bytes;
5267                 trace_btrfs_space_reservation(fs_info, "space_info",
5268                                               space_info->flags, orig_bytes, 1);
5269                 ret = 0;
5270         }
5271
5272         /*
5273          * If we couldn't make a reservation then setup our reservation ticket
5274          * and kick the async worker if it's not already running.
5275          *
5276          * If we are a priority flusher then we just need to add our ticket to
5277          * the list and we will do our own flushing further down.
5278          */
5279         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5280                 ticket.bytes = orig_bytes;
5281                 ticket.error = 0;
5282                 init_waitqueue_head(&ticket.wait);
5283                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5284                         list_add_tail(&ticket.list, &space_info->tickets);
5285                         if (!space_info->flush) {
5286                                 space_info->flush = 1;
5287                                 trace_btrfs_trigger_flush(fs_info,
5288                                                           space_info->flags,
5289                                                           orig_bytes, flush,
5290                                                           "enospc");
5291                                 queue_work(system_unbound_wq,
5292                                            &fs_info->async_reclaim_work);
5293                         }
5294                 } else {
5295                         list_add_tail(&ticket.list,
5296                                       &space_info->priority_tickets);
5297                 }
5298         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5299                 used += orig_bytes;
5300                 /*
5301                  * We will do the space reservation dance during log replay,
5302                  * which means we won't have fs_info->fs_root set, so don't do
5303                  * the async reclaim as we will panic.
5304                  */
5305                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5306                     need_do_async_reclaim(fs_info, space_info,
5307                                           used, system_chunk) &&
5308                     !work_busy(&fs_info->async_reclaim_work)) {
5309                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5310                                                   orig_bytes, flush, "preempt");
5311                         queue_work(system_unbound_wq,
5312                                    &fs_info->async_reclaim_work);
5313                 }
5314         }
5315         spin_unlock(&space_info->lock);
5316         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5317                 return ret;
5318
5319         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5320                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5321                                            orig_bytes);
5322
5323         ret = 0;
5324         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5325         spin_lock(&space_info->lock);
5326         if (ticket.bytes) {
5327                 if (ticket.bytes < orig_bytes) {
5328                         u64 num_bytes = orig_bytes - ticket.bytes;
5329                         space_info->bytes_may_use -= num_bytes;
5330                         trace_btrfs_space_reservation(fs_info, "space_info",
5331                                                       space_info->flags,
5332                                                       num_bytes, 0);
5333
5334                 }
5335                 list_del_init(&ticket.list);
5336                 ret = -ENOSPC;
5337         }
5338         spin_unlock(&space_info->lock);
5339         ASSERT(list_empty(&ticket.list));
5340         return ret;
5341 }
5342
5343 /**
5344  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5345  * @root - the root we're allocating for
5346  * @block_rsv - the block_rsv we're allocating for
5347  * @orig_bytes - the number of bytes we want
5348  * @flush - whether or not we can flush to make our reservation
5349  *
5350  * This will reserve orgi_bytes number of bytes from the space info associated
5351  * with the block_rsv.  If there is not enough space it will make an attempt to
5352  * flush out space to make room.  It will do this by flushing delalloc if
5353  * possible or committing the transaction.  If flush is 0 then no attempts to
5354  * regain reservations will be made and this will fail if there is not enough
5355  * space already.
5356  */
5357 static int reserve_metadata_bytes(struct btrfs_root *root,
5358                                   struct btrfs_block_rsv *block_rsv,
5359                                   u64 orig_bytes,
5360                                   enum btrfs_reserve_flush_enum flush)
5361 {
5362         struct btrfs_fs_info *fs_info = root->fs_info;
5363         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5364         int ret;
5365         bool system_chunk = (root == fs_info->chunk_root);
5366
5367         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5368                                        orig_bytes, flush, system_chunk);
5369         if (ret == -ENOSPC &&
5370             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5371                 if (block_rsv != global_rsv &&
5372                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5373                         ret = 0;
5374         }
5375         if (ret == -ENOSPC) {
5376                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5377                                               block_rsv->space_info->flags,
5378                                               orig_bytes, 1);
5379
5380                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5381                         dump_space_info(fs_info, block_rsv->space_info,
5382                                         orig_bytes, 0);
5383         }
5384         return ret;
5385 }
5386
5387 static struct btrfs_block_rsv *get_block_rsv(
5388                                         const struct btrfs_trans_handle *trans,
5389                                         const struct btrfs_root *root)
5390 {
5391         struct btrfs_fs_info *fs_info = root->fs_info;
5392         struct btrfs_block_rsv *block_rsv = NULL;
5393
5394         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5395             (root == fs_info->csum_root && trans->adding_csums) ||
5396             (root == fs_info->uuid_root))
5397                 block_rsv = trans->block_rsv;
5398
5399         if (!block_rsv)
5400                 block_rsv = root->block_rsv;
5401
5402         if (!block_rsv)
5403                 block_rsv = &fs_info->empty_block_rsv;
5404
5405         return block_rsv;
5406 }
5407
5408 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5409                                u64 num_bytes)
5410 {
5411         int ret = -ENOSPC;
5412         spin_lock(&block_rsv->lock);
5413         if (block_rsv->reserved >= num_bytes) {
5414                 block_rsv->reserved -= num_bytes;
5415                 if (block_rsv->reserved < block_rsv->size)
5416                         block_rsv->full = 0;
5417                 ret = 0;
5418         }
5419         spin_unlock(&block_rsv->lock);
5420         return ret;
5421 }
5422
5423 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5424                                 u64 num_bytes, int update_size)
5425 {
5426         spin_lock(&block_rsv->lock);
5427         block_rsv->reserved += num_bytes;
5428         if (update_size)
5429                 block_rsv->size += num_bytes;
5430         else if (block_rsv->reserved >= block_rsv->size)
5431                 block_rsv->full = 1;
5432         spin_unlock(&block_rsv->lock);
5433 }
5434
5435 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5436                              struct btrfs_block_rsv *dest, u64 num_bytes,
5437                              int min_factor)
5438 {
5439         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5440         u64 min_bytes;
5441
5442         if (global_rsv->space_info != dest->space_info)
5443                 return -ENOSPC;
5444
5445         spin_lock(&global_rsv->lock);
5446         min_bytes = div_factor(global_rsv->size, min_factor);
5447         if (global_rsv->reserved < min_bytes + num_bytes) {
5448                 spin_unlock(&global_rsv->lock);
5449                 return -ENOSPC;
5450         }
5451         global_rsv->reserved -= num_bytes;
5452         if (global_rsv->reserved < global_rsv->size)
5453                 global_rsv->full = 0;
5454         spin_unlock(&global_rsv->lock);
5455
5456         block_rsv_add_bytes(dest, num_bytes, 1);
5457         return 0;
5458 }
5459
5460 /*
5461  * This is for space we already have accounted in space_info->bytes_may_use, so
5462  * basically when we're returning space from block_rsv's.
5463  */
5464 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5465                                      struct btrfs_space_info *space_info,
5466                                      u64 num_bytes)
5467 {
5468         struct reserve_ticket *ticket;
5469         struct list_head *head;
5470         u64 used;
5471         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5472         bool check_overcommit = false;
5473
5474         spin_lock(&space_info->lock);
5475         head = &space_info->priority_tickets;
5476
5477         /*
5478          * If we are over our limit then we need to check and see if we can
5479          * overcommit, and if we can't then we just need to free up our space
5480          * and not satisfy any requests.
5481          */
5482         used = btrfs_space_info_used(space_info, true);
5483         if (used - num_bytes >= space_info->total_bytes)
5484                 check_overcommit = true;
5485 again:
5486         while (!list_empty(head) && num_bytes) {
5487                 ticket = list_first_entry(head, struct reserve_ticket,
5488                                           list);
5489                 /*
5490                  * We use 0 bytes because this space is already reserved, so
5491                  * adding the ticket space would be a double count.
5492                  */
5493                 if (check_overcommit &&
5494                     !can_overcommit(fs_info, space_info, 0, flush, false))
5495                         break;
5496                 if (num_bytes >= ticket->bytes) {
5497                         list_del_init(&ticket->list);
5498                         num_bytes -= ticket->bytes;
5499                         ticket->bytes = 0;
5500                         space_info->tickets_id++;
5501                         wake_up(&ticket->wait);
5502                 } else {
5503                         ticket->bytes -= num_bytes;
5504                         num_bytes = 0;
5505                 }
5506         }
5507
5508         if (num_bytes && head == &space_info->priority_tickets) {
5509                 head = &space_info->tickets;
5510                 flush = BTRFS_RESERVE_FLUSH_ALL;
5511                 goto again;
5512         }
5513         space_info->bytes_may_use -= num_bytes;
5514         trace_btrfs_space_reservation(fs_info, "space_info",
5515                                       space_info->flags, num_bytes, 0);
5516         spin_unlock(&space_info->lock);
5517 }
5518
5519 /*
5520  * This is for newly allocated space that isn't accounted in
5521  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5522  * we use this helper.
5523  */
5524 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5525                                      struct btrfs_space_info *space_info,
5526                                      u64 num_bytes)
5527 {
5528         struct reserve_ticket *ticket;
5529         struct list_head *head = &space_info->priority_tickets;
5530
5531 again:
5532         while (!list_empty(head) && num_bytes) {
5533                 ticket = list_first_entry(head, struct reserve_ticket,
5534                                           list);
5535                 if (num_bytes >= ticket->bytes) {
5536                         trace_btrfs_space_reservation(fs_info, "space_info",
5537                                                       space_info->flags,
5538                                                       ticket->bytes, 1);
5539                         list_del_init(&ticket->list);
5540                         num_bytes -= ticket->bytes;
5541                         space_info->bytes_may_use += ticket->bytes;
5542                         ticket->bytes = 0;
5543                         space_info->tickets_id++;
5544                         wake_up(&ticket->wait);
5545                 } else {
5546                         trace_btrfs_space_reservation(fs_info, "space_info",
5547                                                       space_info->flags,
5548                                                       num_bytes, 1);
5549                         space_info->bytes_may_use += num_bytes;
5550                         ticket->bytes -= num_bytes;
5551                         num_bytes = 0;
5552                 }
5553         }
5554
5555         if (num_bytes && head == &space_info->priority_tickets) {
5556                 head = &space_info->tickets;
5557                 goto again;
5558         }
5559 }
5560
5561 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5562                                     struct btrfs_block_rsv *block_rsv,
5563                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5564 {
5565         struct btrfs_space_info *space_info = block_rsv->space_info;
5566         u64 ret;
5567
5568         spin_lock(&block_rsv->lock);
5569         if (num_bytes == (u64)-1)
5570                 num_bytes = block_rsv->size;
5571         block_rsv->size -= num_bytes;
5572         if (block_rsv->reserved >= block_rsv->size) {
5573                 num_bytes = block_rsv->reserved - block_rsv->size;
5574                 block_rsv->reserved = block_rsv->size;
5575                 block_rsv->full = 1;
5576         } else {
5577                 num_bytes = 0;
5578         }
5579         spin_unlock(&block_rsv->lock);
5580
5581         ret = num_bytes;
5582         if (num_bytes > 0) {
5583                 if (dest) {
5584                         spin_lock(&dest->lock);
5585                         if (!dest->full) {
5586                                 u64 bytes_to_add;
5587
5588                                 bytes_to_add = dest->size - dest->reserved;
5589                                 bytes_to_add = min(num_bytes, bytes_to_add);
5590                                 dest->reserved += bytes_to_add;
5591                                 if (dest->reserved >= dest->size)
5592                                         dest->full = 1;
5593                                 num_bytes -= bytes_to_add;
5594                         }
5595                         spin_unlock(&dest->lock);
5596                 }
5597                 if (num_bytes)
5598                         space_info_add_old_bytes(fs_info, space_info,
5599                                                  num_bytes);
5600         }
5601         return ret;
5602 }
5603
5604 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5605                             struct btrfs_block_rsv *dst, u64 num_bytes,
5606                             int update_size)
5607 {
5608         int ret;
5609
5610         ret = block_rsv_use_bytes(src, num_bytes);
5611         if (ret)
5612                 return ret;
5613
5614         block_rsv_add_bytes(dst, num_bytes, update_size);
5615         return 0;
5616 }
5617
5618 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5619 {
5620         memset(rsv, 0, sizeof(*rsv));
5621         spin_lock_init(&rsv->lock);
5622         rsv->type = type;
5623 }
5624
5625 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5626                                    struct btrfs_block_rsv *rsv,
5627                                    unsigned short type)
5628 {
5629         btrfs_init_block_rsv(rsv, type);
5630         rsv->space_info = __find_space_info(fs_info,
5631                                             BTRFS_BLOCK_GROUP_METADATA);
5632 }
5633
5634 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5635                                               unsigned short type)
5636 {
5637         struct btrfs_block_rsv *block_rsv;
5638
5639         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5640         if (!block_rsv)
5641                 return NULL;
5642
5643         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5644         return block_rsv;
5645 }
5646
5647 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5648                           struct btrfs_block_rsv *rsv)
5649 {
5650         if (!rsv)
5651                 return;
5652         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5653         kfree(rsv);
5654 }
5655
5656 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5657 {
5658         kfree(rsv);
5659 }
5660
5661 int btrfs_block_rsv_add(struct btrfs_root *root,
5662                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5663                         enum btrfs_reserve_flush_enum flush)
5664 {
5665         int ret;
5666
5667         if (num_bytes == 0)
5668                 return 0;
5669
5670         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5671         if (!ret) {
5672                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5673                 return 0;
5674         }
5675
5676         return ret;
5677 }
5678
5679 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5680 {
5681         u64 num_bytes = 0;
5682         int ret = -ENOSPC;
5683
5684         if (!block_rsv)
5685                 return 0;
5686
5687         spin_lock(&block_rsv->lock);
5688         num_bytes = div_factor(block_rsv->size, min_factor);
5689         if (block_rsv->reserved >= num_bytes)
5690                 ret = 0;
5691         spin_unlock(&block_rsv->lock);
5692
5693         return ret;
5694 }
5695
5696 int btrfs_block_rsv_refill(struct btrfs_root *root,
5697                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5698                            enum btrfs_reserve_flush_enum flush)
5699 {
5700         u64 num_bytes = 0;
5701         int ret = -ENOSPC;
5702
5703         if (!block_rsv)
5704                 return 0;
5705
5706         spin_lock(&block_rsv->lock);
5707         num_bytes = min_reserved;
5708         if (block_rsv->reserved >= num_bytes)
5709                 ret = 0;
5710         else
5711                 num_bytes -= block_rsv->reserved;
5712         spin_unlock(&block_rsv->lock);
5713
5714         if (!ret)
5715                 return 0;
5716
5717         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5718         if (!ret) {
5719                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5720                 return 0;
5721         }
5722
5723         return ret;
5724 }
5725
5726 /**
5727  * btrfs_inode_rsv_refill - refill the inode block rsv.
5728  * @inode - the inode we are refilling.
5729  * @flush - the flusing restriction.
5730  *
5731  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5732  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5733  * or return if we already have enough space.  This will also handle the resreve
5734  * tracepoint for the reserved amount.
5735  */
5736 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5737                                   enum btrfs_reserve_flush_enum flush)
5738 {
5739         struct btrfs_root *root = inode->root;
5740         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5741         u64 num_bytes = 0;
5742         int ret = -ENOSPC;
5743
5744         spin_lock(&block_rsv->lock);
5745         if (block_rsv->reserved < block_rsv->size)
5746                 num_bytes = block_rsv->size - block_rsv->reserved;
5747         spin_unlock(&block_rsv->lock);
5748
5749         if (num_bytes == 0)
5750                 return 0;
5751
5752         ret = btrfs_qgroup_reserve_meta_prealloc(root, num_bytes, true);
5753         if (ret)
5754                 return ret;
5755         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5756         if (!ret) {
5757                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5758                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5759                                               btrfs_ino(inode), num_bytes, 1);
5760         }
5761         return ret;
5762 }
5763
5764 /**
5765  * btrfs_inode_rsv_release - release any excessive reservation.
5766  * @inode - the inode we need to release from.
5767  * @qgroup_free - free or convert qgroup meta.
5768  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5769  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5770  *   @qgroup_free is true for error handling, and false for normal release.
5771  *
5772  * This is the same as btrfs_block_rsv_release, except that it handles the
5773  * tracepoint for the reservation.
5774  */
5775 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5776 {
5777         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5778         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5779         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5780         u64 released = 0;
5781
5782         /*
5783          * Since we statically set the block_rsv->size we just want to say we
5784          * are releasing 0 bytes, and then we'll just get the reservation over
5785          * the size free'd.
5786          */
5787         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0);
5788         if (released > 0)
5789                 trace_btrfs_space_reservation(fs_info, "delalloc",
5790                                               btrfs_ino(inode), released, 0);
5791         if (qgroup_free)
5792                 btrfs_qgroup_free_meta_prealloc(inode->root, released);
5793         else
5794                 btrfs_qgroup_convert_reserved_meta(inode->root, released);
5795 }
5796
5797 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5798                              struct btrfs_block_rsv *block_rsv,
5799                              u64 num_bytes)
5800 {
5801         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5802
5803         if (global_rsv == block_rsv ||
5804             block_rsv->space_info != global_rsv->space_info)
5805                 global_rsv = NULL;
5806         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes);
5807 }
5808
5809 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5810 {
5811         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5812         struct btrfs_space_info *sinfo = block_rsv->space_info;
5813         u64 num_bytes;
5814
5815         /*
5816          * The global block rsv is based on the size of the extent tree, the
5817          * checksum tree and the root tree.  If the fs is empty we want to set
5818          * it to a minimal amount for safety.
5819          */
5820         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5821                 btrfs_root_used(&fs_info->csum_root->root_item) +
5822                 btrfs_root_used(&fs_info->tree_root->root_item);
5823         num_bytes = max_t(u64, num_bytes, SZ_16M);
5824
5825         spin_lock(&sinfo->lock);
5826         spin_lock(&block_rsv->lock);
5827
5828         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5829
5830         if (block_rsv->reserved < block_rsv->size) {
5831                 num_bytes = btrfs_space_info_used(sinfo, true);
5832                 if (sinfo->total_bytes > num_bytes) {
5833                         num_bytes = sinfo->total_bytes - num_bytes;
5834                         num_bytes = min(num_bytes,
5835                                         block_rsv->size - block_rsv->reserved);
5836                         block_rsv->reserved += num_bytes;
5837                         sinfo->bytes_may_use += num_bytes;
5838                         trace_btrfs_space_reservation(fs_info, "space_info",
5839                                                       sinfo->flags, num_bytes,
5840                                                       1);
5841                 }
5842         } else if (block_rsv->reserved > block_rsv->size) {
5843                 num_bytes = block_rsv->reserved - block_rsv->size;
5844                 sinfo->bytes_may_use -= num_bytes;
5845                 trace_btrfs_space_reservation(fs_info, "space_info",
5846                                       sinfo->flags, num_bytes, 0);
5847                 block_rsv->reserved = block_rsv->size;
5848         }
5849
5850         if (block_rsv->reserved == block_rsv->size)
5851                 block_rsv->full = 1;
5852         else
5853                 block_rsv->full = 0;
5854
5855         spin_unlock(&block_rsv->lock);
5856         spin_unlock(&sinfo->lock);
5857 }
5858
5859 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5860 {
5861         struct btrfs_space_info *space_info;
5862
5863         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5864         fs_info->chunk_block_rsv.space_info = space_info;
5865
5866         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5867         fs_info->global_block_rsv.space_info = space_info;
5868         fs_info->trans_block_rsv.space_info = space_info;
5869         fs_info->empty_block_rsv.space_info = space_info;
5870         fs_info->delayed_block_rsv.space_info = space_info;
5871
5872         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5873         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5874         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5875         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5876         if (fs_info->quota_root)
5877                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5878         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5879
5880         update_global_block_rsv(fs_info);
5881 }
5882
5883 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5884 {
5885         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5886                                 (u64)-1);
5887         WARN_ON(fs_info->trans_block_rsv.size > 0);
5888         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5889         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5890         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5891         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5892         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5893 }
5894
5895
5896 /*
5897  * To be called after all the new block groups attached to the transaction
5898  * handle have been created (btrfs_create_pending_block_groups()).
5899  */
5900 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5901 {
5902         struct btrfs_fs_info *fs_info = trans->fs_info;
5903
5904         if (!trans->chunk_bytes_reserved)
5905                 return;
5906
5907         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5908
5909         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5910                                 trans->chunk_bytes_reserved);
5911         trans->chunk_bytes_reserved = 0;
5912 }
5913
5914 /* Can only return 0 or -ENOSPC */
5915 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5916                                   struct btrfs_inode *inode)
5917 {
5918         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5919         struct btrfs_root *root = inode->root;
5920         /*
5921          * We always use trans->block_rsv here as we will have reserved space
5922          * for our orphan when starting the transaction, using get_block_rsv()
5923          * here will sometimes make us choose the wrong block rsv as we could be
5924          * doing a reloc inode for a non refcounted root.
5925          */
5926         struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5927         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5928
5929         /*
5930          * We need to hold space in order to delete our orphan item once we've
5931          * added it, so this takes the reservation so we can release it later
5932          * when we are truly done with the orphan item.
5933          */
5934         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5935
5936         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5937                         num_bytes, 1);
5938         return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5939 }
5940
5941 void btrfs_orphan_release_metadata(struct btrfs_inode *inode)
5942 {
5943         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5944         struct btrfs_root *root = inode->root;
5945         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5946
5947         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5948                         num_bytes, 0);
5949         btrfs_block_rsv_release(fs_info, root->orphan_block_rsv, num_bytes);
5950 }
5951
5952 /*
5953  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5954  * root: the root of the parent directory
5955  * rsv: block reservation
5956  * items: the number of items that we need do reservation
5957  * qgroup_reserved: used to return the reserved size in qgroup
5958  *
5959  * This function is used to reserve the space for snapshot/subvolume
5960  * creation and deletion. Those operations are different with the
5961  * common file/directory operations, they change two fs/file trees
5962  * and root tree, the number of items that the qgroup reserves is
5963  * different with the free space reservation. So we can not use
5964  * the space reservation mechanism in start_transaction().
5965  */
5966 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5967                                      struct btrfs_block_rsv *rsv,
5968                                      int items,
5969                                      u64 *qgroup_reserved,
5970                                      bool use_global_rsv)
5971 {
5972         u64 num_bytes;
5973         int ret;
5974         struct btrfs_fs_info *fs_info = root->fs_info;
5975         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5976
5977         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5978                 /* One for parent inode, two for dir entries */
5979                 num_bytes = 3 * fs_info->nodesize;
5980                 ret = btrfs_qgroup_reserve_meta_prealloc(root, num_bytes, true);
5981                 if (ret)
5982                         return ret;
5983         } else {
5984                 num_bytes = 0;
5985         }
5986
5987         *qgroup_reserved = num_bytes;
5988
5989         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5990         rsv->space_info = __find_space_info(fs_info,
5991                                             BTRFS_BLOCK_GROUP_METADATA);
5992         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5993                                   BTRFS_RESERVE_FLUSH_ALL);
5994
5995         if (ret == -ENOSPC && use_global_rsv)
5996                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5997
5998         if (ret && *qgroup_reserved)
5999                 btrfs_qgroup_free_meta_prealloc(root, *qgroup_reserved);
6000
6001         return ret;
6002 }
6003
6004 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
6005                                       struct btrfs_block_rsv *rsv)
6006 {
6007         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
6008 }
6009
6010 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
6011                                                  struct btrfs_inode *inode)
6012 {
6013         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
6014         u64 reserve_size = 0;
6015         u64 csum_leaves;
6016         unsigned outstanding_extents;
6017
6018         lockdep_assert_held(&inode->lock);
6019         outstanding_extents = inode->outstanding_extents;
6020         if (outstanding_extents)
6021                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
6022                                                 outstanding_extents + 1);
6023         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
6024                                                  inode->csum_bytes);
6025         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
6026                                                        csum_leaves);
6027
6028         spin_lock(&block_rsv->lock);
6029         block_rsv->size = reserve_size;
6030         spin_unlock(&block_rsv->lock);
6031 }
6032
6033 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
6034 {
6035         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6036         unsigned nr_extents;
6037         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
6038         int ret = 0;
6039         bool delalloc_lock = true;
6040
6041         /* If we are a free space inode we need to not flush since we will be in
6042          * the middle of a transaction commit.  We also don't need the delalloc
6043          * mutex since we won't race with anybody.  We need this mostly to make
6044          * lockdep shut its filthy mouth.
6045          *
6046          * If we have a transaction open (can happen if we call truncate_block
6047          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
6048          */
6049         if (btrfs_is_free_space_inode(inode)) {
6050                 flush = BTRFS_RESERVE_NO_FLUSH;
6051                 delalloc_lock = false;
6052         } else {
6053                 if (current->journal_info)
6054                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
6055
6056                 if (btrfs_transaction_in_commit(fs_info))
6057                         schedule_timeout(1);
6058         }
6059
6060         if (delalloc_lock)
6061                 mutex_lock(&inode->delalloc_mutex);
6062
6063         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6064
6065         /* Add our new extents and calculate the new rsv size. */
6066         spin_lock(&inode->lock);
6067         nr_extents = count_max_extents(num_bytes);
6068         btrfs_mod_outstanding_extents(inode, nr_extents);
6069         inode->csum_bytes += num_bytes;
6070         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6071         spin_unlock(&inode->lock);
6072
6073         ret = btrfs_inode_rsv_refill(inode, flush);
6074         if (unlikely(ret))
6075                 goto out_fail;
6076
6077         if (delalloc_lock)
6078                 mutex_unlock(&inode->delalloc_mutex);
6079         return 0;
6080
6081 out_fail:
6082         spin_lock(&inode->lock);
6083         nr_extents = count_max_extents(num_bytes);
6084         btrfs_mod_outstanding_extents(inode, -nr_extents);
6085         inode->csum_bytes -= num_bytes;
6086         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6087         spin_unlock(&inode->lock);
6088
6089         btrfs_inode_rsv_release(inode, true);
6090         if (delalloc_lock)
6091                 mutex_unlock(&inode->delalloc_mutex);
6092         return ret;
6093 }
6094
6095 /**
6096  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6097  * @inode: the inode to release the reservation for.
6098  * @num_bytes: the number of bytes we are releasing.
6099  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
6100  *
6101  * This will release the metadata reservation for an inode.  This can be called
6102  * once we complete IO for a given set of bytes to release their metadata
6103  * reservations, or on error for the same reason.
6104  */
6105 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
6106                                      bool qgroup_free)
6107 {
6108         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6109
6110         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6111         spin_lock(&inode->lock);
6112         inode->csum_bytes -= num_bytes;
6113         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6114         spin_unlock(&inode->lock);
6115
6116         if (btrfs_is_testing(fs_info))
6117                 return;
6118
6119         btrfs_inode_rsv_release(inode, qgroup_free);
6120 }
6121
6122 /**
6123  * btrfs_delalloc_release_extents - release our outstanding_extents
6124  * @inode: the inode to balance the reservation for.
6125  * @num_bytes: the number of bytes we originally reserved with
6126  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
6127  *
6128  * When we reserve space we increase outstanding_extents for the extents we may
6129  * add.  Once we've set the range as delalloc or created our ordered extents we
6130  * have outstanding_extents to track the real usage, so we use this to free our
6131  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
6132  * with btrfs_delalloc_reserve_metadata.
6133  */
6134 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
6135                                     bool qgroup_free)
6136 {
6137         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6138         unsigned num_extents;
6139
6140         spin_lock(&inode->lock);
6141         num_extents = count_max_extents(num_bytes);
6142         btrfs_mod_outstanding_extents(inode, -num_extents);
6143         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6144         spin_unlock(&inode->lock);
6145
6146         if (btrfs_is_testing(fs_info))
6147                 return;
6148
6149         btrfs_inode_rsv_release(inode, qgroup_free);
6150 }
6151
6152 /**
6153  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6154  * delalloc
6155  * @inode: inode we're writing to
6156  * @start: start range we are writing to
6157  * @len: how long the range we are writing to
6158  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6159  *            current reservation.
6160  *
6161  * This will do the following things
6162  *
6163  * o reserve space in data space info for num bytes
6164  *   and reserve precious corresponding qgroup space
6165  *   (Done in check_data_free_space)
6166  *
6167  * o reserve space for metadata space, based on the number of outstanding
6168  *   extents and how much csums will be needed
6169  *   also reserve metadata space in a per root over-reserve method.
6170  * o add to the inodes->delalloc_bytes
6171  * o add it to the fs_info's delalloc inodes list.
6172  *   (Above 3 all done in delalloc_reserve_metadata)
6173  *
6174  * Return 0 for success
6175  * Return <0 for error(-ENOSPC or -EQUOT)
6176  */
6177 int btrfs_delalloc_reserve_space(struct inode *inode,
6178                         struct extent_changeset **reserved, u64 start, u64 len)
6179 {
6180         int ret;
6181
6182         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6183         if (ret < 0)
6184                 return ret;
6185         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6186         if (ret < 0)
6187                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6188         return ret;
6189 }
6190
6191 /**
6192  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6193  * @inode: inode we're releasing space for
6194  * @start: start position of the space already reserved
6195  * @len: the len of the space already reserved
6196  * @release_bytes: the len of the space we consumed or didn't use
6197  *
6198  * This function will release the metadata space that was not used and will
6199  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6200  * list if there are no delalloc bytes left.
6201  * Also it will handle the qgroup reserved space.
6202  */
6203 void btrfs_delalloc_release_space(struct inode *inode,
6204                                   struct extent_changeset *reserved,
6205                                   u64 start, u64 len, bool qgroup_free)
6206 {
6207         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6208         btrfs_free_reserved_data_space(inode, reserved, start, len);
6209 }
6210
6211 static int update_block_group(struct btrfs_trans_handle *trans,
6212                               struct btrfs_fs_info *info, u64 bytenr,
6213                               u64 num_bytes, int alloc)
6214 {
6215         struct btrfs_block_group_cache *cache = NULL;
6216         u64 total = num_bytes;
6217         u64 old_val;
6218         u64 byte_in_group;
6219         int factor;
6220
6221         /* block accounting for super block */
6222         spin_lock(&info->delalloc_root_lock);
6223         old_val = btrfs_super_bytes_used(info->super_copy);
6224         if (alloc)
6225                 old_val += num_bytes;
6226         else
6227                 old_val -= num_bytes;
6228         btrfs_set_super_bytes_used(info->super_copy, old_val);
6229         spin_unlock(&info->delalloc_root_lock);
6230
6231         while (total) {
6232                 cache = btrfs_lookup_block_group(info, bytenr);
6233                 if (!cache)
6234                         return -ENOENT;
6235                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6236                                     BTRFS_BLOCK_GROUP_RAID1 |
6237                                     BTRFS_BLOCK_GROUP_RAID10))
6238                         factor = 2;
6239                 else
6240                         factor = 1;
6241                 /*
6242                  * If this block group has free space cache written out, we
6243                  * need to make sure to load it if we are removing space.  This
6244                  * is because we need the unpinning stage to actually add the
6245                  * space back to the block group, otherwise we will leak space.
6246                  */
6247                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6248                         cache_block_group(cache, 1);
6249
6250                 byte_in_group = bytenr - cache->key.objectid;
6251                 WARN_ON(byte_in_group > cache->key.offset);
6252
6253                 spin_lock(&cache->space_info->lock);
6254                 spin_lock(&cache->lock);
6255
6256                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6257                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6258                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6259
6260                 old_val = btrfs_block_group_used(&cache->item);
6261                 num_bytes = min(total, cache->key.offset - byte_in_group);
6262                 if (alloc) {
6263                         old_val += num_bytes;
6264                         btrfs_set_block_group_used(&cache->item, old_val);
6265                         cache->reserved -= num_bytes;
6266                         cache->space_info->bytes_reserved -= num_bytes;
6267                         cache->space_info->bytes_used += num_bytes;
6268                         cache->space_info->disk_used += num_bytes * factor;
6269                         spin_unlock(&cache->lock);
6270                         spin_unlock(&cache->space_info->lock);
6271                 } else {
6272                         old_val -= num_bytes;
6273                         btrfs_set_block_group_used(&cache->item, old_val);
6274                         cache->pinned += num_bytes;
6275                         cache->space_info->bytes_pinned += num_bytes;
6276                         cache->space_info->bytes_used -= num_bytes;
6277                         cache->space_info->disk_used -= num_bytes * factor;
6278                         spin_unlock(&cache->lock);
6279                         spin_unlock(&cache->space_info->lock);
6280
6281                         trace_btrfs_space_reservation(info, "pinned",
6282                                                       cache->space_info->flags,
6283                                                       num_bytes, 1);
6284                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
6285                                            num_bytes);
6286                         set_extent_dirty(info->pinned_extents,
6287                                          bytenr, bytenr + num_bytes - 1,
6288                                          GFP_NOFS | __GFP_NOFAIL);
6289                 }
6290
6291                 spin_lock(&trans->transaction->dirty_bgs_lock);
6292                 if (list_empty(&cache->dirty_list)) {
6293                         list_add_tail(&cache->dirty_list,
6294                                       &trans->transaction->dirty_bgs);
6295                                 trans->transaction->num_dirty_bgs++;
6296                         btrfs_get_block_group(cache);
6297                 }
6298                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6299
6300                 /*
6301                  * No longer have used bytes in this block group, queue it for
6302                  * deletion. We do this after adding the block group to the
6303                  * dirty list to avoid races between cleaner kthread and space
6304                  * cache writeout.
6305                  */
6306                 if (!alloc && old_val == 0) {
6307                         spin_lock(&info->unused_bgs_lock);
6308                         if (list_empty(&cache->bg_list)) {
6309                                 btrfs_get_block_group(cache);
6310                                 list_add_tail(&cache->bg_list,
6311                                               &info->unused_bgs);
6312                         }
6313                         spin_unlock(&info->unused_bgs_lock);
6314                 }
6315
6316                 btrfs_put_block_group(cache);
6317                 total -= num_bytes;
6318                 bytenr += num_bytes;
6319         }
6320         return 0;
6321 }
6322
6323 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6324 {
6325         struct btrfs_block_group_cache *cache;
6326         u64 bytenr;
6327
6328         spin_lock(&fs_info->block_group_cache_lock);
6329         bytenr = fs_info->first_logical_byte;
6330         spin_unlock(&fs_info->block_group_cache_lock);
6331
6332         if (bytenr < (u64)-1)
6333                 return bytenr;
6334
6335         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6336         if (!cache)
6337                 return 0;
6338
6339         bytenr = cache->key.objectid;
6340         btrfs_put_block_group(cache);
6341
6342         return bytenr;
6343 }
6344
6345 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6346                            struct btrfs_block_group_cache *cache,
6347                            u64 bytenr, u64 num_bytes, int reserved)
6348 {
6349         spin_lock(&cache->space_info->lock);
6350         spin_lock(&cache->lock);
6351         cache->pinned += num_bytes;
6352         cache->space_info->bytes_pinned += num_bytes;
6353         if (reserved) {
6354                 cache->reserved -= num_bytes;
6355                 cache->space_info->bytes_reserved -= num_bytes;
6356         }
6357         spin_unlock(&cache->lock);
6358         spin_unlock(&cache->space_info->lock);
6359
6360         trace_btrfs_space_reservation(fs_info, "pinned",
6361                                       cache->space_info->flags, num_bytes, 1);
6362         percpu_counter_add(&cache->space_info->total_bytes_pinned, num_bytes);
6363         set_extent_dirty(fs_info->pinned_extents, bytenr,
6364                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6365         return 0;
6366 }
6367
6368 /*
6369  * this function must be called within transaction
6370  */
6371 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6372                      u64 bytenr, u64 num_bytes, int reserved)
6373 {
6374         struct btrfs_block_group_cache *cache;
6375
6376         cache = btrfs_lookup_block_group(fs_info, bytenr);
6377         BUG_ON(!cache); /* Logic error */
6378
6379         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6380
6381         btrfs_put_block_group(cache);
6382         return 0;
6383 }
6384
6385 /*
6386  * this function must be called within transaction
6387  */
6388 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6389                                     u64 bytenr, u64 num_bytes)
6390 {
6391         struct btrfs_block_group_cache *cache;
6392         int ret;
6393
6394         cache = btrfs_lookup_block_group(fs_info, bytenr);
6395         if (!cache)
6396                 return -EINVAL;
6397
6398         /*
6399          * pull in the free space cache (if any) so that our pin
6400          * removes the free space from the cache.  We have load_only set
6401          * to one because the slow code to read in the free extents does check
6402          * the pinned extents.
6403          */
6404         cache_block_group(cache, 1);
6405
6406         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6407
6408         /* remove us from the free space cache (if we're there at all) */
6409         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6410         btrfs_put_block_group(cache);
6411         return ret;
6412 }
6413
6414 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6415                                    u64 start, u64 num_bytes)
6416 {
6417         int ret;
6418         struct btrfs_block_group_cache *block_group;
6419         struct btrfs_caching_control *caching_ctl;
6420
6421         block_group = btrfs_lookup_block_group(fs_info, start);
6422         if (!block_group)
6423                 return -EINVAL;
6424
6425         cache_block_group(block_group, 0);
6426         caching_ctl = get_caching_control(block_group);
6427
6428         if (!caching_ctl) {
6429                 /* Logic error */
6430                 BUG_ON(!block_group_cache_done(block_group));
6431                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6432         } else {
6433                 mutex_lock(&caching_ctl->mutex);
6434
6435                 if (start >= caching_ctl->progress) {
6436                         ret = add_excluded_extent(fs_info, start, num_bytes);
6437                 } else if (start + num_bytes <= caching_ctl->progress) {
6438                         ret = btrfs_remove_free_space(block_group,
6439                                                       start, num_bytes);
6440                 } else {
6441                         num_bytes = caching_ctl->progress - start;
6442                         ret = btrfs_remove_free_space(block_group,
6443                                                       start, num_bytes);
6444                         if (ret)
6445                                 goto out_lock;
6446
6447                         num_bytes = (start + num_bytes) -
6448                                 caching_ctl->progress;
6449                         start = caching_ctl->progress;
6450                         ret = add_excluded_extent(fs_info, start, num_bytes);
6451                 }
6452 out_lock:
6453                 mutex_unlock(&caching_ctl->mutex);
6454                 put_caching_control(caching_ctl);
6455         }
6456         btrfs_put_block_group(block_group);
6457         return ret;
6458 }
6459
6460 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6461                                  struct extent_buffer *eb)
6462 {
6463         struct btrfs_file_extent_item *item;
6464         struct btrfs_key key;
6465         int found_type;
6466         int i;
6467
6468         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6469                 return 0;
6470
6471         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6472                 btrfs_item_key_to_cpu(eb, &key, i);
6473                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6474                         continue;
6475                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6476                 found_type = btrfs_file_extent_type(eb, item);
6477                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6478                         continue;
6479                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6480                         continue;
6481                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6482                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6483                 __exclude_logged_extent(fs_info, key.objectid, key.offset);
6484         }
6485
6486         return 0;
6487 }
6488
6489 static void
6490 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6491 {
6492         atomic_inc(&bg->reservations);
6493 }
6494
6495 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6496                                         const u64 start)
6497 {
6498         struct btrfs_block_group_cache *bg;
6499
6500         bg = btrfs_lookup_block_group(fs_info, start);
6501         ASSERT(bg);
6502         if (atomic_dec_and_test(&bg->reservations))
6503                 wake_up_atomic_t(&bg->reservations);
6504         btrfs_put_block_group(bg);
6505 }
6506
6507 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6508 {
6509         struct btrfs_space_info *space_info = bg->space_info;
6510
6511         ASSERT(bg->ro);
6512
6513         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6514                 return;
6515
6516         /*
6517          * Our block group is read only but before we set it to read only,
6518          * some task might have had allocated an extent from it already, but it
6519          * has not yet created a respective ordered extent (and added it to a
6520          * root's list of ordered extents).
6521          * Therefore wait for any task currently allocating extents, since the
6522          * block group's reservations counter is incremented while a read lock
6523          * on the groups' semaphore is held and decremented after releasing
6524          * the read access on that semaphore and creating the ordered extent.
6525          */
6526         down_write(&space_info->groups_sem);
6527         up_write(&space_info->groups_sem);
6528
6529         wait_on_atomic_t(&bg->reservations, atomic_t_wait,
6530                          TASK_UNINTERRUPTIBLE);
6531 }
6532
6533 /**
6534  * btrfs_add_reserved_bytes - update the block_group and space info counters
6535  * @cache:      The cache we are manipulating
6536  * @ram_bytes:  The number of bytes of file content, and will be same to
6537  *              @num_bytes except for the compress path.
6538  * @num_bytes:  The number of bytes in question
6539  * @delalloc:   The blocks are allocated for the delalloc write
6540  *
6541  * This is called by the allocator when it reserves space. If this is a
6542  * reservation and the block group has become read only we cannot make the
6543  * reservation and return -EAGAIN, otherwise this function always succeeds.
6544  */
6545 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6546                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6547 {
6548         struct btrfs_space_info *space_info = cache->space_info;
6549         int ret = 0;
6550
6551         spin_lock(&space_info->lock);
6552         spin_lock(&cache->lock);
6553         if (cache->ro) {
6554                 ret = -EAGAIN;
6555         } else {
6556                 cache->reserved += num_bytes;
6557                 space_info->bytes_reserved += num_bytes;
6558
6559                 trace_btrfs_space_reservation(cache->fs_info,
6560                                 "space_info", space_info->flags,
6561                                 ram_bytes, 0);
6562                 space_info->bytes_may_use -= ram_bytes;
6563                 if (delalloc)
6564                         cache->delalloc_bytes += num_bytes;
6565         }
6566         spin_unlock(&cache->lock);
6567         spin_unlock(&space_info->lock);
6568         return ret;
6569 }
6570
6571 /**
6572  * btrfs_free_reserved_bytes - update the block_group and space info counters
6573  * @cache:      The cache we are manipulating
6574  * @num_bytes:  The number of bytes in question
6575  * @delalloc:   The blocks are allocated for the delalloc write
6576  *
6577  * This is called by somebody who is freeing space that was never actually used
6578  * on disk.  For example if you reserve some space for a new leaf in transaction
6579  * A and before transaction A commits you free that leaf, you call this with
6580  * reserve set to 0 in order to clear the reservation.
6581  */
6582
6583 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6584                                      u64 num_bytes, int delalloc)
6585 {
6586         struct btrfs_space_info *space_info = cache->space_info;
6587         int ret = 0;
6588
6589         spin_lock(&space_info->lock);
6590         spin_lock(&cache->lock);
6591         if (cache->ro)
6592                 space_info->bytes_readonly += num_bytes;
6593         cache->reserved -= num_bytes;
6594         space_info->bytes_reserved -= num_bytes;
6595
6596         if (delalloc)
6597                 cache->delalloc_bytes -= num_bytes;
6598         spin_unlock(&cache->lock);
6599         spin_unlock(&space_info->lock);
6600         return ret;
6601 }
6602 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6603 {
6604         struct btrfs_caching_control *next;
6605         struct btrfs_caching_control *caching_ctl;
6606         struct btrfs_block_group_cache *cache;
6607
6608         down_write(&fs_info->commit_root_sem);
6609
6610         list_for_each_entry_safe(caching_ctl, next,
6611                                  &fs_info->caching_block_groups, list) {
6612                 cache = caching_ctl->block_group;
6613                 if (block_group_cache_done(cache)) {
6614                         cache->last_byte_to_unpin = (u64)-1;
6615                         list_del_init(&caching_ctl->list);
6616                         put_caching_control(caching_ctl);
6617                 } else {
6618                         cache->last_byte_to_unpin = caching_ctl->progress;
6619                 }
6620         }
6621
6622         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6623                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6624         else
6625                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6626
6627         up_write(&fs_info->commit_root_sem);
6628
6629         update_global_block_rsv(fs_info);
6630 }
6631
6632 /*
6633  * Returns the free cluster for the given space info and sets empty_cluster to
6634  * what it should be based on the mount options.
6635  */
6636 static struct btrfs_free_cluster *
6637 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6638                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6639 {
6640         struct btrfs_free_cluster *ret = NULL;
6641
6642         *empty_cluster = 0;
6643         if (btrfs_mixed_space_info(space_info))
6644                 return ret;
6645
6646         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6647                 ret = &fs_info->meta_alloc_cluster;
6648                 if (btrfs_test_opt(fs_info, SSD))
6649                         *empty_cluster = SZ_2M;
6650                 else
6651                         *empty_cluster = SZ_64K;
6652         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6653                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6654                 *empty_cluster = SZ_2M;
6655                 ret = &fs_info->data_alloc_cluster;
6656         }
6657
6658         return ret;
6659 }
6660
6661 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6662                               u64 start, u64 end,
6663                               const bool return_free_space)
6664 {
6665         struct btrfs_block_group_cache *cache = NULL;
6666         struct btrfs_space_info *space_info;
6667         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6668         struct btrfs_free_cluster *cluster = NULL;
6669         u64 len;
6670         u64 total_unpinned = 0;
6671         u64 empty_cluster = 0;
6672         bool readonly;
6673
6674         while (start <= end) {
6675                 readonly = false;
6676                 if (!cache ||
6677                     start >= cache->key.objectid + cache->key.offset) {
6678                         if (cache)
6679                                 btrfs_put_block_group(cache);
6680                         total_unpinned = 0;
6681                         cache = btrfs_lookup_block_group(fs_info, start);
6682                         BUG_ON(!cache); /* Logic error */
6683
6684                         cluster = fetch_cluster_info(fs_info,
6685                                                      cache->space_info,
6686                                                      &empty_cluster);
6687                         empty_cluster <<= 1;
6688                 }
6689
6690                 len = cache->key.objectid + cache->key.offset - start;
6691                 len = min(len, end + 1 - start);
6692
6693                 if (start < cache->last_byte_to_unpin) {
6694                         len = min(len, cache->last_byte_to_unpin - start);
6695                         if (return_free_space)
6696                                 btrfs_add_free_space(cache, start, len);
6697                 }
6698
6699                 start += len;
6700                 total_unpinned += len;
6701                 space_info = cache->space_info;
6702
6703                 /*
6704                  * If this space cluster has been marked as fragmented and we've
6705                  * unpinned enough in this block group to potentially allow a
6706                  * cluster to be created inside of it go ahead and clear the
6707                  * fragmented check.
6708                  */
6709                 if (cluster && cluster->fragmented &&
6710                     total_unpinned > empty_cluster) {
6711                         spin_lock(&cluster->lock);
6712                         cluster->fragmented = 0;
6713                         spin_unlock(&cluster->lock);
6714                 }
6715
6716                 spin_lock(&space_info->lock);
6717                 spin_lock(&cache->lock);
6718                 cache->pinned -= len;
6719                 space_info->bytes_pinned -= len;
6720
6721                 trace_btrfs_space_reservation(fs_info, "pinned",
6722                                               space_info->flags, len, 0);
6723                 space_info->max_extent_size = 0;
6724                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6725                 if (cache->ro) {
6726                         space_info->bytes_readonly += len;
6727                         readonly = true;
6728                 }
6729                 spin_unlock(&cache->lock);
6730                 if (!readonly && return_free_space &&
6731                     global_rsv->space_info == space_info) {
6732                         u64 to_add = len;
6733
6734                         spin_lock(&global_rsv->lock);
6735                         if (!global_rsv->full) {
6736                                 to_add = min(len, global_rsv->size -
6737                                              global_rsv->reserved);
6738                                 global_rsv->reserved += to_add;
6739                                 space_info->bytes_may_use += to_add;
6740                                 if (global_rsv->reserved >= global_rsv->size)
6741                                         global_rsv->full = 1;
6742                                 trace_btrfs_space_reservation(fs_info,
6743                                                               "space_info",
6744                                                               space_info->flags,
6745                                                               to_add, 1);
6746                                 len -= to_add;
6747                         }
6748                         spin_unlock(&global_rsv->lock);
6749                         /* Add to any tickets we may have */
6750                         if (len)
6751                                 space_info_add_new_bytes(fs_info, space_info,
6752                                                          len);
6753                 }
6754                 spin_unlock(&space_info->lock);
6755         }
6756
6757         if (cache)
6758                 btrfs_put_block_group(cache);
6759         return 0;
6760 }
6761
6762 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6763 {
6764         struct btrfs_fs_info *fs_info = trans->fs_info;
6765         struct btrfs_block_group_cache *block_group, *tmp;
6766         struct list_head *deleted_bgs;
6767         struct extent_io_tree *unpin;
6768         u64 start;
6769         u64 end;
6770         int ret;
6771
6772         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6773                 unpin = &fs_info->freed_extents[1];
6774         else
6775                 unpin = &fs_info->freed_extents[0];
6776
6777         while (!trans->aborted) {
6778                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6779                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6780                                             EXTENT_DIRTY, NULL);
6781                 if (ret) {
6782                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6783                         break;
6784                 }
6785
6786                 if (btrfs_test_opt(fs_info, DISCARD))
6787                         ret = btrfs_discard_extent(fs_info, start,
6788                                                    end + 1 - start, NULL);
6789
6790                 clear_extent_dirty(unpin, start, end);
6791                 unpin_extent_range(fs_info, start, end, true);
6792                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6793                 cond_resched();
6794         }
6795
6796         /*
6797          * Transaction is finished.  We don't need the lock anymore.  We
6798          * do need to clean up the block groups in case of a transaction
6799          * abort.
6800          */
6801         deleted_bgs = &trans->transaction->deleted_bgs;
6802         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6803                 u64 trimmed = 0;
6804
6805                 ret = -EROFS;
6806                 if (!trans->aborted)
6807                         ret = btrfs_discard_extent(fs_info,
6808                                                    block_group->key.objectid,
6809                                                    block_group->key.offset,
6810                                                    &trimmed);
6811
6812                 list_del_init(&block_group->bg_list);
6813                 btrfs_put_block_group_trimming(block_group);
6814                 btrfs_put_block_group(block_group);
6815
6816                 if (ret) {
6817                         const char *errstr = btrfs_decode_error(ret);
6818                         btrfs_warn(fs_info,
6819                            "discard failed while removing blockgroup: errno=%d %s",
6820                                    ret, errstr);
6821                 }
6822         }
6823
6824         return 0;
6825 }
6826
6827 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6828                                 struct btrfs_fs_info *info,
6829                                 struct btrfs_delayed_ref_node *node, u64 parent,
6830                                 u64 root_objectid, u64 owner_objectid,
6831                                 u64 owner_offset, int refs_to_drop,
6832                                 struct btrfs_delayed_extent_op *extent_op)
6833 {
6834         struct btrfs_key key;
6835         struct btrfs_path *path;
6836         struct btrfs_root *extent_root = info->extent_root;
6837         struct extent_buffer *leaf;
6838         struct btrfs_extent_item *ei;
6839         struct btrfs_extent_inline_ref *iref;
6840         int ret;
6841         int is_data;
6842         int extent_slot = 0;
6843         int found_extent = 0;
6844         int num_to_del = 1;
6845         u32 item_size;
6846         u64 refs;
6847         u64 bytenr = node->bytenr;
6848         u64 num_bytes = node->num_bytes;
6849         int last_ref = 0;
6850         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6851
6852         path = btrfs_alloc_path();
6853         if (!path)
6854                 return -ENOMEM;
6855
6856         path->reada = READA_FORWARD;
6857         path->leave_spinning = 1;
6858
6859         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6860         BUG_ON(!is_data && refs_to_drop != 1);
6861
6862         if (is_data)
6863                 skinny_metadata = false;
6864
6865         ret = lookup_extent_backref(trans, info, path, &iref,
6866                                     bytenr, num_bytes, parent,
6867                                     root_objectid, owner_objectid,
6868                                     owner_offset);
6869         if (ret == 0) {
6870                 extent_slot = path->slots[0];
6871                 while (extent_slot >= 0) {
6872                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6873                                               extent_slot);
6874                         if (key.objectid != bytenr)
6875                                 break;
6876                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6877                             key.offset == num_bytes) {
6878                                 found_extent = 1;
6879                                 break;
6880                         }
6881                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6882                             key.offset == owner_objectid) {
6883                                 found_extent = 1;
6884                                 break;
6885                         }
6886                         if (path->slots[0] - extent_slot > 5)
6887                                 break;
6888                         extent_slot--;
6889                 }
6890 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6891                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6892                 if (found_extent && item_size < sizeof(*ei))
6893                         found_extent = 0;
6894 #endif
6895                 if (!found_extent) {
6896                         BUG_ON(iref);
6897                         ret = remove_extent_backref(trans, info, path, NULL,
6898                                                     refs_to_drop,
6899                                                     is_data, &last_ref);
6900                         if (ret) {
6901                                 btrfs_abort_transaction(trans, ret);
6902                                 goto out;
6903                         }
6904                         btrfs_release_path(path);
6905                         path->leave_spinning = 1;
6906
6907                         key.objectid = bytenr;
6908                         key.type = BTRFS_EXTENT_ITEM_KEY;
6909                         key.offset = num_bytes;
6910
6911                         if (!is_data && skinny_metadata) {
6912                                 key.type = BTRFS_METADATA_ITEM_KEY;
6913                                 key.offset = owner_objectid;
6914                         }
6915
6916                         ret = btrfs_search_slot(trans, extent_root,
6917                                                 &key, path, -1, 1);
6918                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6919                                 /*
6920                                  * Couldn't find our skinny metadata item,
6921                                  * see if we have ye olde extent item.
6922                                  */
6923                                 path->slots[0]--;
6924                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6925                                                       path->slots[0]);
6926                                 if (key.objectid == bytenr &&
6927                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6928                                     key.offset == num_bytes)
6929                                         ret = 0;
6930                         }
6931
6932                         if (ret > 0 && skinny_metadata) {
6933                                 skinny_metadata = false;
6934                                 key.objectid = bytenr;
6935                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6936                                 key.offset = num_bytes;
6937                                 btrfs_release_path(path);
6938                                 ret = btrfs_search_slot(trans, extent_root,
6939                                                         &key, path, -1, 1);
6940                         }
6941
6942                         if (ret) {
6943                                 btrfs_err(info,
6944                                           "umm, got %d back from search, was looking for %llu",
6945                                           ret, bytenr);
6946                                 if (ret > 0)
6947                                         btrfs_print_leaf(path->nodes[0]);
6948                         }
6949                         if (ret < 0) {
6950                                 btrfs_abort_transaction(trans, ret);
6951                                 goto out;
6952                         }
6953                         extent_slot = path->slots[0];
6954                 }
6955         } else if (WARN_ON(ret == -ENOENT)) {
6956                 btrfs_print_leaf(path->nodes[0]);
6957                 btrfs_err(info,
6958                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6959                         bytenr, parent, root_objectid, owner_objectid,
6960                         owner_offset);
6961                 btrfs_abort_transaction(trans, ret);
6962                 goto out;
6963         } else {
6964                 btrfs_abort_transaction(trans, ret);
6965                 goto out;
6966         }
6967
6968         leaf = path->nodes[0];
6969         item_size = btrfs_item_size_nr(leaf, extent_slot);
6970 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6971         if (item_size < sizeof(*ei)) {
6972                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6973                 ret = convert_extent_item_v0(trans, info, path, owner_objectid,
6974                                              0);
6975                 if (ret < 0) {
6976                         btrfs_abort_transaction(trans, ret);
6977                         goto out;
6978                 }
6979
6980                 btrfs_release_path(path);
6981                 path->leave_spinning = 1;
6982
6983                 key.objectid = bytenr;
6984                 key.type = BTRFS_EXTENT_ITEM_KEY;
6985                 key.offset = num_bytes;
6986
6987                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6988                                         -1, 1);
6989                 if (ret) {
6990                         btrfs_err(info,
6991                                   "umm, got %d back from search, was looking for %llu",
6992                                 ret, bytenr);
6993                         btrfs_print_leaf(path->nodes[0]);
6994                 }
6995                 if (ret < 0) {
6996                         btrfs_abort_transaction(trans, ret);
6997                         goto out;
6998                 }
6999
7000                 extent_slot = path->slots[0];
7001                 leaf = path->nodes[0];
7002                 item_size = btrfs_item_size_nr(leaf, extent_slot);
7003         }
7004 #endif
7005         BUG_ON(item_size < sizeof(*ei));
7006         ei = btrfs_item_ptr(leaf, extent_slot,
7007                             struct btrfs_extent_item);
7008         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7009             key.type == BTRFS_EXTENT_ITEM_KEY) {
7010                 struct btrfs_tree_block_info *bi;
7011                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7012                 bi = (struct btrfs_tree_block_info *)(ei + 1);
7013                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7014         }
7015
7016         refs = btrfs_extent_refs(leaf, ei);
7017         if (refs < refs_to_drop) {
7018                 btrfs_err(info,
7019                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7020                           refs_to_drop, refs, bytenr);
7021                 ret = -EINVAL;
7022                 btrfs_abort_transaction(trans, ret);
7023                 goto out;
7024         }
7025         refs -= refs_to_drop;
7026
7027         if (refs > 0) {
7028                 if (extent_op)
7029                         __run_delayed_extent_op(extent_op, leaf, ei);
7030                 /*
7031                  * In the case of inline back ref, reference count will
7032                  * be updated by remove_extent_backref
7033                  */
7034                 if (iref) {
7035                         BUG_ON(!found_extent);
7036                 } else {
7037                         btrfs_set_extent_refs(leaf, ei, refs);
7038                         btrfs_mark_buffer_dirty(leaf);
7039                 }
7040                 if (found_extent) {
7041                         ret = remove_extent_backref(trans, info, path,
7042                                                     iref, refs_to_drop,
7043                                                     is_data, &last_ref);
7044                         if (ret) {
7045                                 btrfs_abort_transaction(trans, ret);
7046                                 goto out;
7047                         }
7048                 }
7049         } else {
7050                 if (found_extent) {
7051                         BUG_ON(is_data && refs_to_drop !=
7052                                extent_data_ref_count(path, iref));
7053                         if (iref) {
7054                                 BUG_ON(path->slots[0] != extent_slot);
7055                         } else {
7056                                 BUG_ON(path->slots[0] != extent_slot + 1);
7057                                 path->slots[0] = extent_slot;
7058                                 num_to_del = 2;
7059                         }
7060                 }
7061
7062                 last_ref = 1;
7063                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7064                                       num_to_del);
7065                 if (ret) {
7066                         btrfs_abort_transaction(trans, ret);
7067                         goto out;
7068                 }
7069                 btrfs_release_path(path);
7070
7071                 if (is_data) {
7072                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
7073                         if (ret) {
7074                                 btrfs_abort_transaction(trans, ret);
7075                                 goto out;
7076                         }
7077                 }
7078
7079                 ret = add_to_free_space_tree(trans, info, bytenr, num_bytes);
7080                 if (ret) {
7081                         btrfs_abort_transaction(trans, ret);
7082                         goto out;
7083                 }
7084
7085                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
7086                 if (ret) {
7087                         btrfs_abort_transaction(trans, ret);
7088                         goto out;
7089                 }
7090         }
7091         btrfs_release_path(path);
7092
7093 out:
7094         btrfs_free_path(path);
7095         return ret;
7096 }
7097
7098 /*
7099  * when we free an block, it is possible (and likely) that we free the last
7100  * delayed ref for that extent as well.  This searches the delayed ref tree for
7101  * a given extent, and if there are no other delayed refs to be processed, it
7102  * removes it from the tree.
7103  */
7104 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7105                                       u64 bytenr)
7106 {
7107         struct btrfs_delayed_ref_head *head;
7108         struct btrfs_delayed_ref_root *delayed_refs;
7109         int ret = 0;
7110
7111         delayed_refs = &trans->transaction->delayed_refs;
7112         spin_lock(&delayed_refs->lock);
7113         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
7114         if (!head)
7115                 goto out_delayed_unlock;
7116
7117         spin_lock(&head->lock);
7118         if (!RB_EMPTY_ROOT(&head->ref_tree))
7119                 goto out;
7120
7121         if (head->extent_op) {
7122                 if (!head->must_insert_reserved)
7123                         goto out;
7124                 btrfs_free_delayed_extent_op(head->extent_op);
7125                 head->extent_op = NULL;
7126         }
7127
7128         /*
7129          * waiting for the lock here would deadlock.  If someone else has it
7130          * locked they are already in the process of dropping it anyway
7131          */
7132         if (!mutex_trylock(&head->mutex))
7133                 goto out;
7134
7135         /*
7136          * at this point we have a head with no other entries.  Go
7137          * ahead and process it.
7138          */
7139         rb_erase(&head->href_node, &delayed_refs->href_root);
7140         RB_CLEAR_NODE(&head->href_node);
7141         atomic_dec(&delayed_refs->num_entries);
7142
7143         /*
7144          * we don't take a ref on the node because we're removing it from the
7145          * tree, so we just steal the ref the tree was holding.
7146          */
7147         delayed_refs->num_heads--;
7148         if (head->processing == 0)
7149                 delayed_refs->num_heads_ready--;
7150         head->processing = 0;
7151         spin_unlock(&head->lock);
7152         spin_unlock(&delayed_refs->lock);
7153
7154         BUG_ON(head->extent_op);
7155         if (head->must_insert_reserved)
7156                 ret = 1;
7157
7158         mutex_unlock(&head->mutex);
7159         btrfs_put_delayed_ref_head(head);
7160         return ret;
7161 out:
7162         spin_unlock(&head->lock);
7163
7164 out_delayed_unlock:
7165         spin_unlock(&delayed_refs->lock);
7166         return 0;
7167 }
7168
7169 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7170                            struct btrfs_root *root,
7171                            struct extent_buffer *buf,
7172                            u64 parent, int last_ref)
7173 {
7174         struct btrfs_fs_info *fs_info = root->fs_info;
7175         int pin = 1;
7176         int ret;
7177
7178         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7179                 int old_ref_mod, new_ref_mod;
7180
7181                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
7182                                    root->root_key.objectid,
7183                                    btrfs_header_level(buf), 0,
7184                                    BTRFS_DROP_DELAYED_REF);
7185                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, buf->start,
7186                                                  buf->len, parent,
7187                                                  root->root_key.objectid,
7188                                                  btrfs_header_level(buf),
7189                                                  BTRFS_DROP_DELAYED_REF, NULL,
7190                                                  &old_ref_mod, &new_ref_mod);
7191                 BUG_ON(ret); /* -ENOMEM */
7192                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7193         }
7194
7195         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7196                 struct btrfs_block_group_cache *cache;
7197
7198                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7199                         ret = check_ref_cleanup(trans, buf->start);
7200                         if (!ret)
7201                                 goto out;
7202                 }
7203
7204                 pin = 0;
7205                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7206
7207                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7208                         pin_down_extent(fs_info, cache, buf->start,
7209                                         buf->len, 1);
7210                         btrfs_put_block_group(cache);
7211                         goto out;
7212                 }
7213
7214                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7215
7216                 btrfs_add_free_space(cache, buf->start, buf->len);
7217                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7218                 btrfs_put_block_group(cache);
7219                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7220         }
7221 out:
7222         if (pin)
7223                 add_pinned_bytes(fs_info, buf->len, btrfs_header_level(buf),
7224                                  root->root_key.objectid);
7225
7226         if (last_ref) {
7227                 /*
7228                  * Deleting the buffer, clear the corrupt flag since it doesn't
7229                  * matter anymore.
7230                  */
7231                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7232         }
7233 }
7234
7235 /* Can return -ENOMEM */
7236 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7237                       struct btrfs_root *root,
7238                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7239                       u64 owner, u64 offset)
7240 {
7241         struct btrfs_fs_info *fs_info = root->fs_info;
7242         int old_ref_mod, new_ref_mod;
7243         int ret;
7244
7245         if (btrfs_is_testing(fs_info))
7246                 return 0;
7247
7248         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7249                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7250                                    root_objectid, owner, offset,
7251                                    BTRFS_DROP_DELAYED_REF);
7252
7253         /*
7254          * tree log blocks never actually go into the extent allocation
7255          * tree, just update pinning info and exit early.
7256          */
7257         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7258                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7259                 /* unlocks the pinned mutex */
7260                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7261                 old_ref_mod = new_ref_mod = 0;
7262                 ret = 0;
7263         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7264                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7265                                                  num_bytes, parent,
7266                                                  root_objectid, (int)owner,
7267                                                  BTRFS_DROP_DELAYED_REF, NULL,
7268                                                  &old_ref_mod, &new_ref_mod);
7269         } else {
7270                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7271                                                  num_bytes, parent,
7272                                                  root_objectid, owner, offset,
7273                                                  0, BTRFS_DROP_DELAYED_REF,
7274                                                  &old_ref_mod, &new_ref_mod);
7275         }
7276
7277         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
7278                 add_pinned_bytes(fs_info, num_bytes, owner, root_objectid);
7279
7280         return ret;
7281 }
7282
7283 /*
7284  * when we wait for progress in the block group caching, its because
7285  * our allocation attempt failed at least once.  So, we must sleep
7286  * and let some progress happen before we try again.
7287  *
7288  * This function will sleep at least once waiting for new free space to
7289  * show up, and then it will check the block group free space numbers
7290  * for our min num_bytes.  Another option is to have it go ahead
7291  * and look in the rbtree for a free extent of a given size, but this
7292  * is a good start.
7293  *
7294  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7295  * any of the information in this block group.
7296  */
7297 static noinline void
7298 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7299                                 u64 num_bytes)
7300 {
7301         struct btrfs_caching_control *caching_ctl;
7302
7303         caching_ctl = get_caching_control(cache);
7304         if (!caching_ctl)
7305                 return;
7306
7307         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7308                    (cache->free_space_ctl->free_space >= num_bytes));
7309
7310         put_caching_control(caching_ctl);
7311 }
7312
7313 static noinline int
7314 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7315 {
7316         struct btrfs_caching_control *caching_ctl;
7317         int ret = 0;
7318
7319         caching_ctl = get_caching_control(cache);
7320         if (!caching_ctl)
7321                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7322
7323         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7324         if (cache->cached == BTRFS_CACHE_ERROR)
7325                 ret = -EIO;
7326         put_caching_control(caching_ctl);
7327         return ret;
7328 }
7329
7330 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7331         [BTRFS_RAID_RAID10]     = "raid10",
7332         [BTRFS_RAID_RAID1]      = "raid1",
7333         [BTRFS_RAID_DUP]        = "dup",
7334         [BTRFS_RAID_RAID0]      = "raid0",
7335         [BTRFS_RAID_SINGLE]     = "single",
7336         [BTRFS_RAID_RAID5]      = "raid5",
7337         [BTRFS_RAID_RAID6]      = "raid6",
7338 };
7339
7340 static const char *get_raid_name(enum btrfs_raid_types type)
7341 {
7342         if (type >= BTRFS_NR_RAID_TYPES)
7343                 return NULL;
7344
7345         return btrfs_raid_type_names[type];
7346 }
7347
7348 enum btrfs_loop_type {
7349         LOOP_CACHING_NOWAIT = 0,
7350         LOOP_CACHING_WAIT = 1,
7351         LOOP_ALLOC_CHUNK = 2,
7352         LOOP_NO_EMPTY_SIZE = 3,
7353 };
7354
7355 static inline void
7356 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7357                        int delalloc)
7358 {
7359         if (delalloc)
7360                 down_read(&cache->data_rwsem);
7361 }
7362
7363 static inline void
7364 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7365                        int delalloc)
7366 {
7367         btrfs_get_block_group(cache);
7368         if (delalloc)
7369                 down_read(&cache->data_rwsem);
7370 }
7371
7372 static struct btrfs_block_group_cache *
7373 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7374                    struct btrfs_free_cluster *cluster,
7375                    int delalloc)
7376 {
7377         struct btrfs_block_group_cache *used_bg = NULL;
7378
7379         spin_lock(&cluster->refill_lock);
7380         while (1) {
7381                 used_bg = cluster->block_group;
7382                 if (!used_bg)
7383                         return NULL;
7384
7385                 if (used_bg == block_group)
7386                         return used_bg;
7387
7388                 btrfs_get_block_group(used_bg);
7389
7390                 if (!delalloc)
7391                         return used_bg;
7392
7393                 if (down_read_trylock(&used_bg->data_rwsem))
7394                         return used_bg;
7395
7396                 spin_unlock(&cluster->refill_lock);
7397
7398                 /* We should only have one-level nested. */
7399                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7400
7401                 spin_lock(&cluster->refill_lock);
7402                 if (used_bg == cluster->block_group)
7403                         return used_bg;
7404
7405                 up_read(&used_bg->data_rwsem);
7406                 btrfs_put_block_group(used_bg);
7407         }
7408 }
7409
7410 static inline void
7411 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7412                          int delalloc)
7413 {
7414         if (delalloc)
7415                 up_read(&cache->data_rwsem);
7416         btrfs_put_block_group(cache);
7417 }
7418
7419 /*
7420  * walks the btree of allocated extents and find a hole of a given size.
7421  * The key ins is changed to record the hole:
7422  * ins->objectid == start position
7423  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7424  * ins->offset == the size of the hole.
7425  * Any available blocks before search_start are skipped.
7426  *
7427  * If there is no suitable free space, we will record the max size of
7428  * the free space extent currently.
7429  */
7430 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7431                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7432                                 u64 hint_byte, struct btrfs_key *ins,
7433                                 u64 flags, int delalloc)
7434 {
7435         int ret = 0;
7436         struct btrfs_root *root = fs_info->extent_root;
7437         struct btrfs_free_cluster *last_ptr = NULL;
7438         struct btrfs_block_group_cache *block_group = NULL;
7439         u64 search_start = 0;
7440         u64 max_extent_size = 0;
7441         u64 empty_cluster = 0;
7442         struct btrfs_space_info *space_info;
7443         int loop = 0;
7444         int index = btrfs_bg_flags_to_raid_index(flags);
7445         bool failed_cluster_refill = false;
7446         bool failed_alloc = false;
7447         bool use_cluster = true;
7448         bool have_caching_bg = false;
7449         bool orig_have_caching_bg = false;
7450         bool full_search = false;
7451
7452         WARN_ON(num_bytes < fs_info->sectorsize);
7453         ins->type = BTRFS_EXTENT_ITEM_KEY;
7454         ins->objectid = 0;
7455         ins->offset = 0;
7456
7457         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7458
7459         space_info = __find_space_info(fs_info, flags);
7460         if (!space_info) {
7461                 btrfs_err(fs_info, "No space info for %llu", flags);
7462                 return -ENOSPC;
7463         }
7464
7465         /*
7466          * If our free space is heavily fragmented we may not be able to make
7467          * big contiguous allocations, so instead of doing the expensive search
7468          * for free space, simply return ENOSPC with our max_extent_size so we
7469          * can go ahead and search for a more manageable chunk.
7470          *
7471          * If our max_extent_size is large enough for our allocation simply
7472          * disable clustering since we will likely not be able to find enough
7473          * space to create a cluster and induce latency trying.
7474          */
7475         if (unlikely(space_info->max_extent_size)) {
7476                 spin_lock(&space_info->lock);
7477                 if (space_info->max_extent_size &&
7478                     num_bytes > space_info->max_extent_size) {
7479                         ins->offset = space_info->max_extent_size;
7480                         spin_unlock(&space_info->lock);
7481                         return -ENOSPC;
7482                 } else if (space_info->max_extent_size) {
7483                         use_cluster = false;
7484                 }
7485                 spin_unlock(&space_info->lock);
7486         }
7487
7488         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7489         if (last_ptr) {
7490                 spin_lock(&last_ptr->lock);
7491                 if (last_ptr->block_group)
7492                         hint_byte = last_ptr->window_start;
7493                 if (last_ptr->fragmented) {
7494                         /*
7495                          * We still set window_start so we can keep track of the
7496                          * last place we found an allocation to try and save
7497                          * some time.
7498                          */
7499                         hint_byte = last_ptr->window_start;
7500                         use_cluster = false;
7501                 }
7502                 spin_unlock(&last_ptr->lock);
7503         }
7504
7505         search_start = max(search_start, first_logical_byte(fs_info, 0));
7506         search_start = max(search_start, hint_byte);
7507         if (search_start == hint_byte) {
7508                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7509                 /*
7510                  * we don't want to use the block group if it doesn't match our
7511                  * allocation bits, or if its not cached.
7512                  *
7513                  * However if we are re-searching with an ideal block group
7514                  * picked out then we don't care that the block group is cached.
7515                  */
7516                 if (block_group && block_group_bits(block_group, flags) &&
7517                     block_group->cached != BTRFS_CACHE_NO) {
7518                         down_read(&space_info->groups_sem);
7519                         if (list_empty(&block_group->list) ||
7520                             block_group->ro) {
7521                                 /*
7522                                  * someone is removing this block group,
7523                                  * we can't jump into the have_block_group
7524                                  * target because our list pointers are not
7525                                  * valid
7526                                  */
7527                                 btrfs_put_block_group(block_group);
7528                                 up_read(&space_info->groups_sem);
7529                         } else {
7530                                 index = btrfs_bg_flags_to_raid_index(
7531                                                 block_group->flags);
7532                                 btrfs_lock_block_group(block_group, delalloc);
7533                                 goto have_block_group;
7534                         }
7535                 } else if (block_group) {
7536                         btrfs_put_block_group(block_group);
7537                 }
7538         }
7539 search:
7540         have_caching_bg = false;
7541         if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
7542                 full_search = true;
7543         down_read(&space_info->groups_sem);
7544         list_for_each_entry(block_group, &space_info->block_groups[index],
7545                             list) {
7546                 u64 offset;
7547                 int cached;
7548
7549                 /* If the block group is read-only, we can skip it entirely. */
7550                 if (unlikely(block_group->ro))
7551                         continue;
7552
7553                 btrfs_grab_block_group(block_group, delalloc);
7554                 search_start = block_group->key.objectid;
7555
7556                 /*
7557                  * this can happen if we end up cycling through all the
7558                  * raid types, but we want to make sure we only allocate
7559                  * for the proper type.
7560                  */
7561                 if (!block_group_bits(block_group, flags)) {
7562                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7563                                 BTRFS_BLOCK_GROUP_RAID1 |
7564                                 BTRFS_BLOCK_GROUP_RAID5 |
7565                                 BTRFS_BLOCK_GROUP_RAID6 |
7566                                 BTRFS_BLOCK_GROUP_RAID10;
7567
7568                         /*
7569                          * if they asked for extra copies and this block group
7570                          * doesn't provide them, bail.  This does allow us to
7571                          * fill raid0 from raid1.
7572                          */
7573                         if ((flags & extra) && !(block_group->flags & extra))
7574                                 goto loop;
7575                 }
7576
7577 have_block_group:
7578                 cached = block_group_cache_done(block_group);
7579                 if (unlikely(!cached)) {
7580                         have_caching_bg = true;
7581                         ret = cache_block_group(block_group, 0);
7582                         BUG_ON(ret < 0);
7583                         ret = 0;
7584                 }
7585
7586                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7587                         goto loop;
7588
7589                 /*
7590                  * Ok we want to try and use the cluster allocator, so
7591                  * lets look there
7592                  */
7593                 if (last_ptr && use_cluster) {
7594                         struct btrfs_block_group_cache *used_block_group;
7595                         unsigned long aligned_cluster;
7596                         /*
7597                          * the refill lock keeps out other
7598                          * people trying to start a new cluster
7599                          */
7600                         used_block_group = btrfs_lock_cluster(block_group,
7601                                                               last_ptr,
7602                                                               delalloc);
7603                         if (!used_block_group)
7604                                 goto refill_cluster;
7605
7606                         if (used_block_group != block_group &&
7607                             (used_block_group->ro ||
7608                              !block_group_bits(used_block_group, flags)))
7609                                 goto release_cluster;
7610
7611                         offset = btrfs_alloc_from_cluster(used_block_group,
7612                                                 last_ptr,
7613                                                 num_bytes,
7614                                                 used_block_group->key.objectid,
7615                                                 &max_extent_size);
7616                         if (offset) {
7617                                 /* we have a block, we're done */
7618                                 spin_unlock(&last_ptr->refill_lock);
7619                                 trace_btrfs_reserve_extent_cluster(fs_info,
7620                                                 used_block_group,
7621                                                 search_start, num_bytes);
7622                                 if (used_block_group != block_group) {
7623                                         btrfs_release_block_group(block_group,
7624                                                                   delalloc);
7625                                         block_group = used_block_group;
7626                                 }
7627                                 goto checks;
7628                         }
7629
7630                         WARN_ON(last_ptr->block_group != used_block_group);
7631 release_cluster:
7632                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7633                          * set up a new clusters, so lets just skip it
7634                          * and let the allocator find whatever block
7635                          * it can find.  If we reach this point, we
7636                          * will have tried the cluster allocator
7637                          * plenty of times and not have found
7638                          * anything, so we are likely way too
7639                          * fragmented for the clustering stuff to find
7640                          * anything.
7641                          *
7642                          * However, if the cluster is taken from the
7643                          * current block group, release the cluster
7644                          * first, so that we stand a better chance of
7645                          * succeeding in the unclustered
7646                          * allocation.  */
7647                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7648                             used_block_group != block_group) {
7649                                 spin_unlock(&last_ptr->refill_lock);
7650                                 btrfs_release_block_group(used_block_group,
7651                                                           delalloc);
7652                                 goto unclustered_alloc;
7653                         }
7654
7655                         /*
7656                          * this cluster didn't work out, free it and
7657                          * start over
7658                          */
7659                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7660
7661                         if (used_block_group != block_group)
7662                                 btrfs_release_block_group(used_block_group,
7663                                                           delalloc);
7664 refill_cluster:
7665                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7666                                 spin_unlock(&last_ptr->refill_lock);
7667                                 goto unclustered_alloc;
7668                         }
7669
7670                         aligned_cluster = max_t(unsigned long,
7671                                                 empty_cluster + empty_size,
7672                                               block_group->full_stripe_len);
7673
7674                         /* allocate a cluster in this block group */
7675                         ret = btrfs_find_space_cluster(fs_info, block_group,
7676                                                        last_ptr, search_start,
7677                                                        num_bytes,
7678                                                        aligned_cluster);
7679                         if (ret == 0) {
7680                                 /*
7681                                  * now pull our allocation out of this
7682                                  * cluster
7683                                  */
7684                                 offset = btrfs_alloc_from_cluster(block_group,
7685                                                         last_ptr,
7686                                                         num_bytes,
7687                                                         search_start,
7688                                                         &max_extent_size);
7689                                 if (offset) {
7690                                         /* we found one, proceed */
7691                                         spin_unlock(&last_ptr->refill_lock);
7692                                         trace_btrfs_reserve_extent_cluster(fs_info,
7693                                                 block_group, search_start,
7694                                                 num_bytes);
7695                                         goto checks;
7696                                 }
7697                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7698                                    && !failed_cluster_refill) {
7699                                 spin_unlock(&last_ptr->refill_lock);
7700
7701                                 failed_cluster_refill = true;
7702                                 wait_block_group_cache_progress(block_group,
7703                                        num_bytes + empty_cluster + empty_size);
7704                                 goto have_block_group;
7705                         }
7706
7707                         /*
7708                          * at this point we either didn't find a cluster
7709                          * or we weren't able to allocate a block from our
7710                          * cluster.  Free the cluster we've been trying
7711                          * to use, and go to the next block group
7712                          */
7713                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7714                         spin_unlock(&last_ptr->refill_lock);
7715                         goto loop;
7716                 }
7717
7718 unclustered_alloc:
7719                 /*
7720                  * We are doing an unclustered alloc, set the fragmented flag so
7721                  * we don't bother trying to setup a cluster again until we get
7722                  * more space.
7723                  */
7724                 if (unlikely(last_ptr)) {
7725                         spin_lock(&last_ptr->lock);
7726                         last_ptr->fragmented = 1;
7727                         spin_unlock(&last_ptr->lock);
7728                 }
7729                 if (cached) {
7730                         struct btrfs_free_space_ctl *ctl =
7731                                 block_group->free_space_ctl;
7732
7733                         spin_lock(&ctl->tree_lock);
7734                         if (ctl->free_space <
7735                             num_bytes + empty_cluster + empty_size) {
7736                                 if (ctl->free_space > max_extent_size)
7737                                         max_extent_size = ctl->free_space;
7738                                 spin_unlock(&ctl->tree_lock);
7739                                 goto loop;
7740                         }
7741                         spin_unlock(&ctl->tree_lock);
7742                 }
7743
7744                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7745                                                     num_bytes, empty_size,
7746                                                     &max_extent_size);
7747                 /*
7748                  * If we didn't find a chunk, and we haven't failed on this
7749                  * block group before, and this block group is in the middle of
7750                  * caching and we are ok with waiting, then go ahead and wait
7751                  * for progress to be made, and set failed_alloc to true.
7752                  *
7753                  * If failed_alloc is true then we've already waited on this
7754                  * block group once and should move on to the next block group.
7755                  */
7756                 if (!offset && !failed_alloc && !cached &&
7757                     loop > LOOP_CACHING_NOWAIT) {
7758                         wait_block_group_cache_progress(block_group,
7759                                                 num_bytes + empty_size);
7760                         failed_alloc = true;
7761                         goto have_block_group;
7762                 } else if (!offset) {
7763                         goto loop;
7764                 }
7765 checks:
7766                 search_start = ALIGN(offset, fs_info->stripesize);
7767
7768                 /* move on to the next group */
7769                 if (search_start + num_bytes >
7770                     block_group->key.objectid + block_group->key.offset) {
7771                         btrfs_add_free_space(block_group, offset, num_bytes);
7772                         goto loop;
7773                 }
7774
7775                 if (offset < search_start)
7776                         btrfs_add_free_space(block_group, offset,
7777                                              search_start - offset);
7778                 BUG_ON(offset > search_start);
7779
7780                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7781                                 num_bytes, delalloc);
7782                 if (ret == -EAGAIN) {
7783                         btrfs_add_free_space(block_group, offset, num_bytes);
7784                         goto loop;
7785                 }
7786                 btrfs_inc_block_group_reservations(block_group);
7787
7788                 /* we are all good, lets return */
7789                 ins->objectid = search_start;
7790                 ins->offset = num_bytes;
7791
7792                 trace_btrfs_reserve_extent(fs_info, block_group,
7793                                            search_start, num_bytes);
7794                 btrfs_release_block_group(block_group, delalloc);
7795                 break;
7796 loop:
7797                 failed_cluster_refill = false;
7798                 failed_alloc = false;
7799                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7800                        index);
7801                 btrfs_release_block_group(block_group, delalloc);
7802                 cond_resched();
7803         }
7804         up_read(&space_info->groups_sem);
7805
7806         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7807                 && !orig_have_caching_bg)
7808                 orig_have_caching_bg = true;
7809
7810         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7811                 goto search;
7812
7813         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7814                 goto search;
7815
7816         /*
7817          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7818          *                      caching kthreads as we move along
7819          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7820          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7821          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7822          *                      again
7823          */
7824         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7825                 index = 0;
7826                 if (loop == LOOP_CACHING_NOWAIT) {
7827                         /*
7828                          * We want to skip the LOOP_CACHING_WAIT step if we
7829                          * don't have any uncached bgs and we've already done a
7830                          * full search through.
7831                          */
7832                         if (orig_have_caching_bg || !full_search)
7833                                 loop = LOOP_CACHING_WAIT;
7834                         else
7835                                 loop = LOOP_ALLOC_CHUNK;
7836                 } else {
7837                         loop++;
7838                 }
7839
7840                 if (loop == LOOP_ALLOC_CHUNK) {
7841                         struct btrfs_trans_handle *trans;
7842                         int exist = 0;
7843
7844                         trans = current->journal_info;
7845                         if (trans)
7846                                 exist = 1;
7847                         else
7848                                 trans = btrfs_join_transaction(root);
7849
7850                         if (IS_ERR(trans)) {
7851                                 ret = PTR_ERR(trans);
7852                                 goto out;
7853                         }
7854
7855                         ret = do_chunk_alloc(trans, fs_info, flags,
7856                                              CHUNK_ALLOC_FORCE);
7857
7858                         /*
7859                          * If we can't allocate a new chunk we've already looped
7860                          * through at least once, move on to the NO_EMPTY_SIZE
7861                          * case.
7862                          */
7863                         if (ret == -ENOSPC)
7864                                 loop = LOOP_NO_EMPTY_SIZE;
7865
7866                         /*
7867                          * Do not bail out on ENOSPC since we
7868                          * can do more things.
7869                          */
7870                         if (ret < 0 && ret != -ENOSPC)
7871                                 btrfs_abort_transaction(trans, ret);
7872                         else
7873                                 ret = 0;
7874                         if (!exist)
7875                                 btrfs_end_transaction(trans);
7876                         if (ret)
7877                                 goto out;
7878                 }
7879
7880                 if (loop == LOOP_NO_EMPTY_SIZE) {
7881                         /*
7882                          * Don't loop again if we already have no empty_size and
7883                          * no empty_cluster.
7884                          */
7885                         if (empty_size == 0 &&
7886                             empty_cluster == 0) {
7887                                 ret = -ENOSPC;
7888                                 goto out;
7889                         }
7890                         empty_size = 0;
7891                         empty_cluster = 0;
7892                 }
7893
7894                 goto search;
7895         } else if (!ins->objectid) {
7896                 ret = -ENOSPC;
7897         } else if (ins->objectid) {
7898                 if (!use_cluster && last_ptr) {
7899                         spin_lock(&last_ptr->lock);
7900                         last_ptr->window_start = ins->objectid;
7901                         spin_unlock(&last_ptr->lock);
7902                 }
7903                 ret = 0;
7904         }
7905 out:
7906         if (ret == -ENOSPC) {
7907                 spin_lock(&space_info->lock);
7908                 space_info->max_extent_size = max_extent_size;
7909                 spin_unlock(&space_info->lock);
7910                 ins->offset = max_extent_size;
7911         }
7912         return ret;
7913 }
7914
7915 static void dump_space_info(struct btrfs_fs_info *fs_info,
7916                             struct btrfs_space_info *info, u64 bytes,
7917                             int dump_block_groups)
7918 {
7919         struct btrfs_block_group_cache *cache;
7920         int index = 0;
7921
7922         spin_lock(&info->lock);
7923         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7924                    info->flags,
7925                    info->total_bytes - btrfs_space_info_used(info, true),
7926                    info->full ? "" : "not ");
7927         btrfs_info(fs_info,
7928                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7929                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7930                 info->bytes_reserved, info->bytes_may_use,
7931                 info->bytes_readonly);
7932         spin_unlock(&info->lock);
7933
7934         if (!dump_block_groups)
7935                 return;
7936
7937         down_read(&info->groups_sem);
7938 again:
7939         list_for_each_entry(cache, &info->block_groups[index], list) {
7940                 spin_lock(&cache->lock);
7941                 btrfs_info(fs_info,
7942                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7943                         cache->key.objectid, cache->key.offset,
7944                         btrfs_block_group_used(&cache->item), cache->pinned,
7945                         cache->reserved, cache->ro ? "[readonly]" : "");
7946                 btrfs_dump_free_space(cache, bytes);
7947                 spin_unlock(&cache->lock);
7948         }
7949         if (++index < BTRFS_NR_RAID_TYPES)
7950                 goto again;
7951         up_read(&info->groups_sem);
7952 }
7953
7954 /*
7955  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7956  *                        hole that is at least as big as @num_bytes.
7957  *
7958  * @root           -    The root that will contain this extent
7959  *
7960  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7961  *                      is used for accounting purposes. This value differs
7962  *                      from @num_bytes only in the case of compressed extents.
7963  *
7964  * @num_bytes      -    Number of bytes to allocate on-disk.
7965  *
7966  * @min_alloc_size -    Indicates the minimum amount of space that the
7967  *                      allocator should try to satisfy. In some cases
7968  *                      @num_bytes may be larger than what is required and if
7969  *                      the filesystem is fragmented then allocation fails.
7970  *                      However, the presence of @min_alloc_size gives a
7971  *                      chance to try and satisfy the smaller allocation.
7972  *
7973  * @empty_size     -    A hint that you plan on doing more COW. This is the
7974  *                      size in bytes the allocator should try to find free
7975  *                      next to the block it returns.  This is just a hint and
7976  *                      may be ignored by the allocator.
7977  *
7978  * @hint_byte      -    Hint to the allocator to start searching above the byte
7979  *                      address passed. It might be ignored.
7980  *
7981  * @ins            -    This key is modified to record the found hole. It will
7982  *                      have the following values:
7983  *                      ins->objectid == start position
7984  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7985  *                      ins->offset == the size of the hole.
7986  *
7987  * @is_data        -    Boolean flag indicating whether an extent is
7988  *                      allocated for data (true) or metadata (false)
7989  *
7990  * @delalloc       -    Boolean flag indicating whether this allocation is for
7991  *                      delalloc or not. If 'true' data_rwsem of block groups
7992  *                      is going to be acquired.
7993  *
7994  *
7995  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7996  * case -ENOSPC is returned then @ins->offset will contain the size of the
7997  * largest available hole the allocator managed to find.
7998  */
7999 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
8000                          u64 num_bytes, u64 min_alloc_size,
8001                          u64 empty_size, u64 hint_byte,
8002                          struct btrfs_key *ins, int is_data, int delalloc)
8003 {
8004         struct btrfs_fs_info *fs_info = root->fs_info;
8005         bool final_tried = num_bytes == min_alloc_size;
8006         u64 flags;
8007         int ret;
8008
8009         flags = get_alloc_profile_by_root(root, is_data);
8010 again:
8011         WARN_ON(num_bytes < fs_info->sectorsize);
8012         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
8013                                hint_byte, ins, flags, delalloc);
8014         if (!ret && !is_data) {
8015                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
8016         } else if (ret == -ENOSPC) {
8017                 if (!final_tried && ins->offset) {
8018                         num_bytes = min(num_bytes >> 1, ins->offset);
8019                         num_bytes = round_down(num_bytes,
8020                                                fs_info->sectorsize);
8021                         num_bytes = max(num_bytes, min_alloc_size);
8022                         ram_bytes = num_bytes;
8023                         if (num_bytes == min_alloc_size)
8024                                 final_tried = true;
8025                         goto again;
8026                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8027                         struct btrfs_space_info *sinfo;
8028
8029                         sinfo = __find_space_info(fs_info, flags);
8030                         btrfs_err(fs_info,
8031                                   "allocation failed flags %llu, wanted %llu",
8032                                   flags, num_bytes);
8033                         if (sinfo)
8034                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
8035                 }
8036         }
8037
8038         return ret;
8039 }
8040
8041 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8042                                         u64 start, u64 len,
8043                                         int pin, int delalloc)
8044 {
8045         struct btrfs_block_group_cache *cache;
8046         int ret = 0;
8047
8048         cache = btrfs_lookup_block_group(fs_info, start);
8049         if (!cache) {
8050                 btrfs_err(fs_info, "Unable to find block group for %llu",
8051                           start);
8052                 return -ENOSPC;
8053         }
8054
8055         if (pin)
8056                 pin_down_extent(fs_info, cache, start, len, 1);
8057         else {
8058                 if (btrfs_test_opt(fs_info, DISCARD))
8059                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8060                 btrfs_add_free_space(cache, start, len);
8061                 btrfs_free_reserved_bytes(cache, len, delalloc);
8062                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8063         }
8064
8065         btrfs_put_block_group(cache);
8066         return ret;
8067 }
8068
8069 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8070                                u64 start, u64 len, int delalloc)
8071 {
8072         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8073 }
8074
8075 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8076                                        u64 start, u64 len)
8077 {
8078         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8079 }
8080
8081 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8082                                       struct btrfs_fs_info *fs_info,
8083                                       u64 parent, u64 root_objectid,
8084                                       u64 flags, u64 owner, u64 offset,
8085                                       struct btrfs_key *ins, int ref_mod)
8086 {
8087         int ret;
8088         struct btrfs_extent_item *extent_item;
8089         struct btrfs_extent_inline_ref *iref;
8090         struct btrfs_path *path;
8091         struct extent_buffer *leaf;
8092         int type;
8093         u32 size;
8094
8095         if (parent > 0)
8096                 type = BTRFS_SHARED_DATA_REF_KEY;
8097         else
8098                 type = BTRFS_EXTENT_DATA_REF_KEY;
8099
8100         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8101
8102         path = btrfs_alloc_path();
8103         if (!path)
8104                 return -ENOMEM;
8105
8106         path->leave_spinning = 1;
8107         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8108                                       ins, size);
8109         if (ret) {
8110                 btrfs_free_path(path);
8111                 return ret;
8112         }
8113
8114         leaf = path->nodes[0];
8115         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8116                                      struct btrfs_extent_item);
8117         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8118         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8119         btrfs_set_extent_flags(leaf, extent_item,
8120                                flags | BTRFS_EXTENT_FLAG_DATA);
8121
8122         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8123         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8124         if (parent > 0) {
8125                 struct btrfs_shared_data_ref *ref;
8126                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8127                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8128                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8129         } else {
8130                 struct btrfs_extent_data_ref *ref;
8131                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8132                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8133                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8134                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8135                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8136         }
8137
8138         btrfs_mark_buffer_dirty(path->nodes[0]);
8139         btrfs_free_path(path);
8140
8141         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8142                                           ins->offset);
8143         if (ret)
8144                 return ret;
8145
8146         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8147         if (ret) { /* -ENOENT, logic error */
8148                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8149                         ins->objectid, ins->offset);
8150                 BUG();
8151         }
8152         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8153         return ret;
8154 }
8155
8156 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8157                                      struct btrfs_fs_info *fs_info,
8158                                      u64 parent, u64 root_objectid,
8159                                      u64 flags, struct btrfs_disk_key *key,
8160                                      int level, struct btrfs_key *ins)
8161 {
8162         int ret;
8163         struct btrfs_extent_item *extent_item;
8164         struct btrfs_tree_block_info *block_info;
8165         struct btrfs_extent_inline_ref *iref;
8166         struct btrfs_path *path;
8167         struct extent_buffer *leaf;
8168         u32 size = sizeof(*extent_item) + sizeof(*iref);
8169         u64 num_bytes = ins->offset;
8170         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8171
8172         if (!skinny_metadata)
8173                 size += sizeof(*block_info);
8174
8175         path = btrfs_alloc_path();
8176         if (!path) {
8177                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8178                                                    fs_info->nodesize);
8179                 return -ENOMEM;
8180         }
8181
8182         path->leave_spinning = 1;
8183         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8184                                       ins, size);
8185         if (ret) {
8186                 btrfs_free_path(path);
8187                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8188                                                    fs_info->nodesize);
8189                 return ret;
8190         }
8191
8192         leaf = path->nodes[0];
8193         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8194                                      struct btrfs_extent_item);
8195         btrfs_set_extent_refs(leaf, extent_item, 1);
8196         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8197         btrfs_set_extent_flags(leaf, extent_item,
8198                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8199
8200         if (skinny_metadata) {
8201                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8202                 num_bytes = fs_info->nodesize;
8203         } else {
8204                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8205                 btrfs_set_tree_block_key(leaf, block_info, key);
8206                 btrfs_set_tree_block_level(leaf, block_info, level);
8207                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8208         }
8209
8210         if (parent > 0) {
8211                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8212                 btrfs_set_extent_inline_ref_type(leaf, iref,
8213                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8214                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8215         } else {
8216                 btrfs_set_extent_inline_ref_type(leaf, iref,
8217                                                  BTRFS_TREE_BLOCK_REF_KEY);
8218                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8219         }
8220
8221         btrfs_mark_buffer_dirty(leaf);
8222         btrfs_free_path(path);
8223
8224         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8225                                           num_bytes);
8226         if (ret)
8227                 return ret;
8228
8229         ret = update_block_group(trans, fs_info, ins->objectid,
8230                                  fs_info->nodesize, 1);
8231         if (ret) { /* -ENOENT, logic error */
8232                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8233                         ins->objectid, ins->offset);
8234                 BUG();
8235         }
8236
8237         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid,
8238                                           fs_info->nodesize);
8239         return ret;
8240 }
8241
8242 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8243                                      struct btrfs_root *root, u64 owner,
8244                                      u64 offset, u64 ram_bytes,
8245                                      struct btrfs_key *ins)
8246 {
8247         struct btrfs_fs_info *fs_info = root->fs_info;
8248         int ret;
8249
8250         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8251
8252         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8253                            root->root_key.objectid, owner, offset,
8254                            BTRFS_ADD_DELAYED_EXTENT);
8255
8256         ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
8257                                          ins->offset, 0,
8258                                          root->root_key.objectid, owner,
8259                                          offset, ram_bytes,
8260                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8261         return ret;
8262 }
8263
8264 /*
8265  * this is used by the tree logging recovery code.  It records that
8266  * an extent has been allocated and makes sure to clear the free
8267  * space cache bits as well
8268  */
8269 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8270                                    struct btrfs_fs_info *fs_info,
8271                                    u64 root_objectid, u64 owner, u64 offset,
8272                                    struct btrfs_key *ins)
8273 {
8274         int ret;
8275         struct btrfs_block_group_cache *block_group;
8276         struct btrfs_space_info *space_info;
8277
8278         /*
8279          * Mixed block groups will exclude before processing the log so we only
8280          * need to do the exclude dance if this fs isn't mixed.
8281          */
8282         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8283                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8284                                               ins->offset);
8285                 if (ret)
8286                         return ret;
8287         }
8288
8289         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8290         if (!block_group)
8291                 return -EINVAL;
8292
8293         space_info = block_group->space_info;
8294         spin_lock(&space_info->lock);
8295         spin_lock(&block_group->lock);
8296         space_info->bytes_reserved += ins->offset;
8297         block_group->reserved += ins->offset;
8298         spin_unlock(&block_group->lock);
8299         spin_unlock(&space_info->lock);
8300
8301         ret = alloc_reserved_file_extent(trans, fs_info, 0, root_objectid,
8302                                          0, owner, offset, ins, 1);
8303         btrfs_put_block_group(block_group);
8304         return ret;
8305 }
8306
8307 static struct extent_buffer *
8308 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8309                       u64 bytenr, int level)
8310 {
8311         struct btrfs_fs_info *fs_info = root->fs_info;
8312         struct extent_buffer *buf;
8313
8314         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8315         if (IS_ERR(buf))
8316                 return buf;
8317
8318         btrfs_set_header_generation(buf, trans->transid);
8319         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8320         btrfs_tree_lock(buf);
8321         clean_tree_block(fs_info, buf);
8322         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8323
8324         btrfs_set_lock_blocking(buf);
8325         set_extent_buffer_uptodate(buf);
8326
8327         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8328                 buf->log_index = root->log_transid % 2;
8329                 /*
8330                  * we allow two log transactions at a time, use different
8331                  * EXENT bit to differentiate dirty pages.
8332                  */
8333                 if (buf->log_index == 0)
8334                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8335                                         buf->start + buf->len - 1, GFP_NOFS);
8336                 else
8337                         set_extent_new(&root->dirty_log_pages, buf->start,
8338                                         buf->start + buf->len - 1);
8339         } else {
8340                 buf->log_index = -1;
8341                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8342                          buf->start + buf->len - 1, GFP_NOFS);
8343         }
8344         trans->dirty = true;
8345         /* this returns a buffer locked for blocking */
8346         return buf;
8347 }
8348
8349 static struct btrfs_block_rsv *
8350 use_block_rsv(struct btrfs_trans_handle *trans,
8351               struct btrfs_root *root, u32 blocksize)
8352 {
8353         struct btrfs_fs_info *fs_info = root->fs_info;
8354         struct btrfs_block_rsv *block_rsv;
8355         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8356         int ret;
8357         bool global_updated = false;
8358
8359         block_rsv = get_block_rsv(trans, root);
8360
8361         if (unlikely(block_rsv->size == 0))
8362                 goto try_reserve;
8363 again:
8364         ret = block_rsv_use_bytes(block_rsv, blocksize);
8365         if (!ret)
8366                 return block_rsv;
8367
8368         if (block_rsv->failfast)
8369                 return ERR_PTR(ret);
8370
8371         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8372                 global_updated = true;
8373                 update_global_block_rsv(fs_info);
8374                 goto again;
8375         }
8376
8377         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8378                 static DEFINE_RATELIMIT_STATE(_rs,
8379                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8380                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8381                 if (__ratelimit(&_rs))
8382                         WARN(1, KERN_DEBUG
8383                                 "BTRFS: block rsv returned %d\n", ret);
8384         }
8385 try_reserve:
8386         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8387                                      BTRFS_RESERVE_NO_FLUSH);
8388         if (!ret)
8389                 return block_rsv;
8390         /*
8391          * If we couldn't reserve metadata bytes try and use some from
8392          * the global reserve if its space type is the same as the global
8393          * reservation.
8394          */
8395         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8396             block_rsv->space_info == global_rsv->space_info) {
8397                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8398                 if (!ret)
8399                         return global_rsv;
8400         }
8401         return ERR_PTR(ret);
8402 }
8403
8404 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8405                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8406 {
8407         block_rsv_add_bytes(block_rsv, blocksize, 0);
8408         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8409 }
8410
8411 /*
8412  * finds a free extent and does all the dirty work required for allocation
8413  * returns the tree buffer or an ERR_PTR on error.
8414  */
8415 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8416                                              struct btrfs_root *root,
8417                                              u64 parent, u64 root_objectid,
8418                                              const struct btrfs_disk_key *key,
8419                                              int level, u64 hint,
8420                                              u64 empty_size)
8421 {
8422         struct btrfs_fs_info *fs_info = root->fs_info;
8423         struct btrfs_key ins;
8424         struct btrfs_block_rsv *block_rsv;
8425         struct extent_buffer *buf;
8426         struct btrfs_delayed_extent_op *extent_op;
8427         u64 flags = 0;
8428         int ret;
8429         u32 blocksize = fs_info->nodesize;
8430         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8431
8432 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8433         if (btrfs_is_testing(fs_info)) {
8434                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8435                                             level);
8436                 if (!IS_ERR(buf))
8437                         root->alloc_bytenr += blocksize;
8438                 return buf;
8439         }
8440 #endif
8441
8442         block_rsv = use_block_rsv(trans, root, blocksize);
8443         if (IS_ERR(block_rsv))
8444                 return ERR_CAST(block_rsv);
8445
8446         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8447                                    empty_size, hint, &ins, 0, 0);
8448         if (ret)
8449                 goto out_unuse;
8450
8451         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8452         if (IS_ERR(buf)) {
8453                 ret = PTR_ERR(buf);
8454                 goto out_free_reserved;
8455         }
8456
8457         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8458                 if (parent == 0)
8459                         parent = ins.objectid;
8460                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8461         } else
8462                 BUG_ON(parent > 0);
8463
8464         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8465                 extent_op = btrfs_alloc_delayed_extent_op();
8466                 if (!extent_op) {
8467                         ret = -ENOMEM;
8468                         goto out_free_buf;
8469                 }
8470                 if (key)
8471                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8472                 else
8473                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8474                 extent_op->flags_to_set = flags;
8475                 extent_op->update_key = skinny_metadata ? false : true;
8476                 extent_op->update_flags = true;
8477                 extent_op->is_data = false;
8478                 extent_op->level = level;
8479
8480                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8481                                    root_objectid, level, 0,
8482                                    BTRFS_ADD_DELAYED_EXTENT);
8483                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, ins.objectid,
8484                                                  ins.offset, parent,
8485                                                  root_objectid, level,
8486                                                  BTRFS_ADD_DELAYED_EXTENT,
8487                                                  extent_op, NULL, NULL);
8488                 if (ret)
8489                         goto out_free_delayed;
8490         }
8491         return buf;
8492
8493 out_free_delayed:
8494         btrfs_free_delayed_extent_op(extent_op);
8495 out_free_buf:
8496         free_extent_buffer(buf);
8497 out_free_reserved:
8498         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8499 out_unuse:
8500         unuse_block_rsv(fs_info, block_rsv, blocksize);
8501         return ERR_PTR(ret);
8502 }
8503
8504 struct walk_control {
8505         u64 refs[BTRFS_MAX_LEVEL];
8506         u64 flags[BTRFS_MAX_LEVEL];
8507         struct btrfs_key update_progress;
8508         int stage;
8509         int level;
8510         int shared_level;
8511         int update_ref;
8512         int keep_locks;
8513         int reada_slot;
8514         int reada_count;
8515         int for_reloc;
8516 };
8517
8518 #define DROP_REFERENCE  1
8519 #define UPDATE_BACKREF  2
8520
8521 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8522                                      struct btrfs_root *root,
8523                                      struct walk_control *wc,
8524                                      struct btrfs_path *path)
8525 {
8526         struct btrfs_fs_info *fs_info = root->fs_info;
8527         u64 bytenr;
8528         u64 generation;
8529         u64 refs;
8530         u64 flags;
8531         u32 nritems;
8532         struct btrfs_key key;
8533         struct extent_buffer *eb;
8534         int ret;
8535         int slot;
8536         int nread = 0;
8537
8538         if (path->slots[wc->level] < wc->reada_slot) {
8539                 wc->reada_count = wc->reada_count * 2 / 3;
8540                 wc->reada_count = max(wc->reada_count, 2);
8541         } else {
8542                 wc->reada_count = wc->reada_count * 3 / 2;
8543                 wc->reada_count = min_t(int, wc->reada_count,
8544                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8545         }
8546
8547         eb = path->nodes[wc->level];
8548         nritems = btrfs_header_nritems(eb);
8549
8550         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8551                 if (nread >= wc->reada_count)
8552                         break;
8553
8554                 cond_resched();
8555                 bytenr = btrfs_node_blockptr(eb, slot);
8556                 generation = btrfs_node_ptr_generation(eb, slot);
8557
8558                 if (slot == path->slots[wc->level])
8559                         goto reada;
8560
8561                 if (wc->stage == UPDATE_BACKREF &&
8562                     generation <= root->root_key.offset)
8563                         continue;
8564
8565                 /* We don't lock the tree block, it's OK to be racy here */
8566                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8567                                                wc->level - 1, 1, &refs,
8568                                                &flags);
8569                 /* We don't care about errors in readahead. */
8570                 if (ret < 0)
8571                         continue;
8572                 BUG_ON(refs == 0);
8573
8574                 if (wc->stage == DROP_REFERENCE) {
8575                         if (refs == 1)
8576                                 goto reada;
8577
8578                         if (wc->level == 1 &&
8579                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8580                                 continue;
8581                         if (!wc->update_ref ||
8582                             generation <= root->root_key.offset)
8583                                 continue;
8584                         btrfs_node_key_to_cpu(eb, &key, slot);
8585                         ret = btrfs_comp_cpu_keys(&key,
8586                                                   &wc->update_progress);
8587                         if (ret < 0)
8588                                 continue;
8589                 } else {
8590                         if (wc->level == 1 &&
8591                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8592                                 continue;
8593                 }
8594 reada:
8595                 readahead_tree_block(fs_info, bytenr);
8596                 nread++;
8597         }
8598         wc->reada_slot = slot;
8599 }
8600
8601 /*
8602  * helper to process tree block while walking down the tree.
8603  *
8604  * when wc->stage == UPDATE_BACKREF, this function updates
8605  * back refs for pointers in the block.
8606  *
8607  * NOTE: return value 1 means we should stop walking down.
8608  */
8609 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8610                                    struct btrfs_root *root,
8611                                    struct btrfs_path *path,
8612                                    struct walk_control *wc, int lookup_info)
8613 {
8614         struct btrfs_fs_info *fs_info = root->fs_info;
8615         int level = wc->level;
8616         struct extent_buffer *eb = path->nodes[level];
8617         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8618         int ret;
8619
8620         if (wc->stage == UPDATE_BACKREF &&
8621             btrfs_header_owner(eb) != root->root_key.objectid)
8622                 return 1;
8623
8624         /*
8625          * when reference count of tree block is 1, it won't increase
8626          * again. once full backref flag is set, we never clear it.
8627          */
8628         if (lookup_info &&
8629             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8630              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8631                 BUG_ON(!path->locks[level]);
8632                 ret = btrfs_lookup_extent_info(trans, fs_info,
8633                                                eb->start, level, 1,
8634                                                &wc->refs[level],
8635                                                &wc->flags[level]);
8636                 BUG_ON(ret == -ENOMEM);
8637                 if (ret)
8638                         return ret;
8639                 BUG_ON(wc->refs[level] == 0);
8640         }
8641
8642         if (wc->stage == DROP_REFERENCE) {
8643                 if (wc->refs[level] > 1)
8644                         return 1;
8645
8646                 if (path->locks[level] && !wc->keep_locks) {
8647                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8648                         path->locks[level] = 0;
8649                 }
8650                 return 0;
8651         }
8652
8653         /* wc->stage == UPDATE_BACKREF */
8654         if (!(wc->flags[level] & flag)) {
8655                 BUG_ON(!path->locks[level]);
8656                 ret = btrfs_inc_ref(trans, root, eb, 1);
8657                 BUG_ON(ret); /* -ENOMEM */
8658                 ret = btrfs_dec_ref(trans, root, eb, 0);
8659                 BUG_ON(ret); /* -ENOMEM */
8660                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8661                                                   eb->len, flag,
8662                                                   btrfs_header_level(eb), 0);
8663                 BUG_ON(ret); /* -ENOMEM */
8664                 wc->flags[level] |= flag;
8665         }
8666
8667         /*
8668          * the block is shared by multiple trees, so it's not good to
8669          * keep the tree lock
8670          */
8671         if (path->locks[level] && level > 0) {
8672                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8673                 path->locks[level] = 0;
8674         }
8675         return 0;
8676 }
8677
8678 /*
8679  * helper to process tree block pointer.
8680  *
8681  * when wc->stage == DROP_REFERENCE, this function checks
8682  * reference count of the block pointed to. if the block
8683  * is shared and we need update back refs for the subtree
8684  * rooted at the block, this function changes wc->stage to
8685  * UPDATE_BACKREF. if the block is shared and there is no
8686  * need to update back, this function drops the reference
8687  * to the block.
8688  *
8689  * NOTE: return value 1 means we should stop walking down.
8690  */
8691 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8692                                  struct btrfs_root *root,
8693                                  struct btrfs_path *path,
8694                                  struct walk_control *wc, int *lookup_info)
8695 {
8696         struct btrfs_fs_info *fs_info = root->fs_info;
8697         u64 bytenr;
8698         u64 generation;
8699         u64 parent;
8700         u32 blocksize;
8701         struct btrfs_key key;
8702         struct btrfs_key first_key;
8703         struct extent_buffer *next;
8704         int level = wc->level;
8705         int reada = 0;
8706         int ret = 0;
8707         bool need_account = false;
8708
8709         generation = btrfs_node_ptr_generation(path->nodes[level],
8710                                                path->slots[level]);
8711         /*
8712          * if the lower level block was created before the snapshot
8713          * was created, we know there is no need to update back refs
8714          * for the subtree
8715          */
8716         if (wc->stage == UPDATE_BACKREF &&
8717             generation <= root->root_key.offset) {
8718                 *lookup_info = 1;
8719                 return 1;
8720         }
8721
8722         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8723         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8724                               path->slots[level]);
8725         blocksize = fs_info->nodesize;
8726
8727         next = find_extent_buffer(fs_info, bytenr);
8728         if (!next) {
8729                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8730                 if (IS_ERR(next))
8731                         return PTR_ERR(next);
8732
8733                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8734                                                level - 1);
8735                 reada = 1;
8736         }
8737         btrfs_tree_lock(next);
8738         btrfs_set_lock_blocking(next);
8739
8740         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8741                                        &wc->refs[level - 1],
8742                                        &wc->flags[level - 1]);
8743         if (ret < 0)
8744                 goto out_unlock;
8745
8746         if (unlikely(wc->refs[level - 1] == 0)) {
8747                 btrfs_err(fs_info, "Missing references.");
8748                 ret = -EIO;
8749                 goto out_unlock;
8750         }
8751         *lookup_info = 0;
8752
8753         if (wc->stage == DROP_REFERENCE) {
8754                 if (wc->refs[level - 1] > 1) {
8755                         need_account = true;
8756                         if (level == 1 &&
8757                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8758                                 goto skip;
8759
8760                         if (!wc->update_ref ||
8761                             generation <= root->root_key.offset)
8762                                 goto skip;
8763
8764                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8765                                               path->slots[level]);
8766                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8767                         if (ret < 0)
8768                                 goto skip;
8769
8770                         wc->stage = UPDATE_BACKREF;
8771                         wc->shared_level = level - 1;
8772                 }
8773         } else {
8774                 if (level == 1 &&
8775                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8776                         goto skip;
8777         }
8778
8779         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8780                 btrfs_tree_unlock(next);
8781                 free_extent_buffer(next);
8782                 next = NULL;
8783                 *lookup_info = 1;
8784         }
8785
8786         if (!next) {
8787                 if (reada && level == 1)
8788                         reada_walk_down(trans, root, wc, path);
8789                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8790                                        &first_key);
8791                 if (IS_ERR(next)) {
8792                         return PTR_ERR(next);
8793                 } else if (!extent_buffer_uptodate(next)) {
8794                         free_extent_buffer(next);
8795                         return -EIO;
8796                 }
8797                 btrfs_tree_lock(next);
8798                 btrfs_set_lock_blocking(next);
8799         }
8800
8801         level--;
8802         ASSERT(level == btrfs_header_level(next));
8803         if (level != btrfs_header_level(next)) {
8804                 btrfs_err(root->fs_info, "mismatched level");
8805                 ret = -EIO;
8806                 goto out_unlock;
8807         }
8808         path->nodes[level] = next;
8809         path->slots[level] = 0;
8810         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8811         wc->level = level;
8812         if (wc->level == 1)
8813                 wc->reada_slot = 0;
8814         return 0;
8815 skip:
8816         wc->refs[level - 1] = 0;
8817         wc->flags[level - 1] = 0;
8818         if (wc->stage == DROP_REFERENCE) {
8819                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8820                         parent = path->nodes[level]->start;
8821                 } else {
8822                         ASSERT(root->root_key.objectid ==
8823                                btrfs_header_owner(path->nodes[level]));
8824                         if (root->root_key.objectid !=
8825                             btrfs_header_owner(path->nodes[level])) {
8826                                 btrfs_err(root->fs_info,
8827                                                 "mismatched block owner");
8828                                 ret = -EIO;
8829                                 goto out_unlock;
8830                         }
8831                         parent = 0;
8832                 }
8833
8834                 if (need_account) {
8835                         ret = btrfs_qgroup_trace_subtree(trans, root, next,
8836                                                          generation, level - 1);
8837                         if (ret) {
8838                                 btrfs_err_rl(fs_info,
8839                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8840                                              ret);
8841                         }
8842                 }
8843                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8844                                         parent, root->root_key.objectid,
8845                                         level - 1, 0);
8846                 if (ret)
8847                         goto out_unlock;
8848         }
8849
8850         *lookup_info = 1;
8851         ret = 1;
8852
8853 out_unlock:
8854         btrfs_tree_unlock(next);
8855         free_extent_buffer(next);
8856
8857         return ret;
8858 }
8859
8860 /*
8861  * helper to process tree block while walking up the tree.
8862  *
8863  * when wc->stage == DROP_REFERENCE, this function drops
8864  * reference count on the block.
8865  *
8866  * when wc->stage == UPDATE_BACKREF, this function changes
8867  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8868  * to UPDATE_BACKREF previously while processing the block.
8869  *
8870  * NOTE: return value 1 means we should stop walking up.
8871  */
8872 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8873                                  struct btrfs_root *root,
8874                                  struct btrfs_path *path,
8875                                  struct walk_control *wc)
8876 {
8877         struct btrfs_fs_info *fs_info = root->fs_info;
8878         int ret;
8879         int level = wc->level;
8880         struct extent_buffer *eb = path->nodes[level];
8881         u64 parent = 0;
8882
8883         if (wc->stage == UPDATE_BACKREF) {
8884                 BUG_ON(wc->shared_level < level);
8885                 if (level < wc->shared_level)
8886                         goto out;
8887
8888                 ret = find_next_key(path, level + 1, &wc->update_progress);
8889                 if (ret > 0)
8890                         wc->update_ref = 0;
8891
8892                 wc->stage = DROP_REFERENCE;
8893                 wc->shared_level = -1;
8894                 path->slots[level] = 0;
8895
8896                 /*
8897                  * check reference count again if the block isn't locked.
8898                  * we should start walking down the tree again if reference
8899                  * count is one.
8900                  */
8901                 if (!path->locks[level]) {
8902                         BUG_ON(level == 0);
8903                         btrfs_tree_lock(eb);
8904                         btrfs_set_lock_blocking(eb);
8905                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8906
8907                         ret = btrfs_lookup_extent_info(trans, fs_info,
8908                                                        eb->start, level, 1,
8909                                                        &wc->refs[level],
8910                                                        &wc->flags[level]);
8911                         if (ret < 0) {
8912                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8913                                 path->locks[level] = 0;
8914                                 return ret;
8915                         }
8916                         BUG_ON(wc->refs[level] == 0);
8917                         if (wc->refs[level] == 1) {
8918                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8919                                 path->locks[level] = 0;
8920                                 return 1;
8921                         }
8922                 }
8923         }
8924
8925         /* wc->stage == DROP_REFERENCE */
8926         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8927
8928         if (wc->refs[level] == 1) {
8929                 if (level == 0) {
8930                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8931                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8932                         else
8933                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8934                         BUG_ON(ret); /* -ENOMEM */
8935                         ret = btrfs_qgroup_trace_leaf_items(trans, fs_info, eb);
8936                         if (ret) {
8937                                 btrfs_err_rl(fs_info,
8938                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8939                                              ret);
8940                         }
8941                 }
8942                 /* make block locked assertion in clean_tree_block happy */
8943                 if (!path->locks[level] &&
8944                     btrfs_header_generation(eb) == trans->transid) {
8945                         btrfs_tree_lock(eb);
8946                         btrfs_set_lock_blocking(eb);
8947                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8948                 }
8949                 clean_tree_block(fs_info, eb);
8950         }
8951
8952         if (eb == root->node) {
8953                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8954                         parent = eb->start;
8955                 else
8956                         BUG_ON(root->root_key.objectid !=
8957                                btrfs_header_owner(eb));
8958         } else {
8959                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8960                         parent = path->nodes[level + 1]->start;
8961                 else
8962                         BUG_ON(root->root_key.objectid !=
8963                                btrfs_header_owner(path->nodes[level + 1]));
8964         }
8965
8966         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8967 out:
8968         wc->refs[level] = 0;
8969         wc->flags[level] = 0;
8970         return 0;
8971 }
8972
8973 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8974                                    struct btrfs_root *root,
8975                                    struct btrfs_path *path,
8976                                    struct walk_control *wc)
8977 {
8978         int level = wc->level;
8979         int lookup_info = 1;
8980         int ret;
8981
8982         while (level >= 0) {
8983                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8984                 if (ret > 0)
8985                         break;
8986
8987                 if (level == 0)
8988                         break;
8989
8990                 if (path->slots[level] >=
8991                     btrfs_header_nritems(path->nodes[level]))
8992                         break;
8993
8994                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8995                 if (ret > 0) {
8996                         path->slots[level]++;
8997                         continue;
8998                 } else if (ret < 0)
8999                         return ret;
9000                 level = wc->level;
9001         }
9002         return 0;
9003 }
9004
9005 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9006                                  struct btrfs_root *root,
9007                                  struct btrfs_path *path,
9008                                  struct walk_control *wc, int max_level)
9009 {
9010         int level = wc->level;
9011         int ret;
9012
9013         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9014         while (level < max_level && path->nodes[level]) {
9015                 wc->level = level;
9016                 if (path->slots[level] + 1 <
9017                     btrfs_header_nritems(path->nodes[level])) {
9018                         path->slots[level]++;
9019                         return 0;
9020                 } else {
9021                         ret = walk_up_proc(trans, root, path, wc);
9022                         if (ret > 0)
9023                                 return 0;
9024
9025                         if (path->locks[level]) {
9026                                 btrfs_tree_unlock_rw(path->nodes[level],
9027                                                      path->locks[level]);
9028                                 path->locks[level] = 0;
9029                         }
9030                         free_extent_buffer(path->nodes[level]);
9031                         path->nodes[level] = NULL;
9032                         level++;
9033                 }
9034         }
9035         return 1;
9036 }
9037
9038 /*
9039  * drop a subvolume tree.
9040  *
9041  * this function traverses the tree freeing any blocks that only
9042  * referenced by the tree.
9043  *
9044  * when a shared tree block is found. this function decreases its
9045  * reference count by one. if update_ref is true, this function
9046  * also make sure backrefs for the shared block and all lower level
9047  * blocks are properly updated.
9048  *
9049  * If called with for_reloc == 0, may exit early with -EAGAIN
9050  */
9051 int btrfs_drop_snapshot(struct btrfs_root *root,
9052                          struct btrfs_block_rsv *block_rsv, int update_ref,
9053                          int for_reloc)
9054 {
9055         struct btrfs_fs_info *fs_info = root->fs_info;
9056         struct btrfs_path *path;
9057         struct btrfs_trans_handle *trans;
9058         struct btrfs_root *tree_root = fs_info->tree_root;
9059         struct btrfs_root_item *root_item = &root->root_item;
9060         struct walk_control *wc;
9061         struct btrfs_key key;
9062         int err = 0;
9063         int ret;
9064         int level;
9065         bool root_dropped = false;
9066
9067         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9068
9069         path = btrfs_alloc_path();
9070         if (!path) {
9071                 err = -ENOMEM;
9072                 goto out;
9073         }
9074
9075         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9076         if (!wc) {
9077                 btrfs_free_path(path);
9078                 err = -ENOMEM;
9079                 goto out;
9080         }
9081
9082         trans = btrfs_start_transaction(tree_root, 0);
9083         if (IS_ERR(trans)) {
9084                 err = PTR_ERR(trans);
9085                 goto out_free;
9086         }
9087
9088         if (block_rsv)
9089                 trans->block_rsv = block_rsv;
9090
9091         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9092                 level = btrfs_header_level(root->node);
9093                 path->nodes[level] = btrfs_lock_root_node(root);
9094                 btrfs_set_lock_blocking(path->nodes[level]);
9095                 path->slots[level] = 0;
9096                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9097                 memset(&wc->update_progress, 0,
9098                        sizeof(wc->update_progress));
9099         } else {
9100                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9101                 memcpy(&wc->update_progress, &key,
9102                        sizeof(wc->update_progress));
9103
9104                 level = root_item->drop_level;
9105                 BUG_ON(level == 0);
9106                 path->lowest_level = level;
9107                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9108                 path->lowest_level = 0;
9109                 if (ret < 0) {
9110                         err = ret;
9111                         goto out_end_trans;
9112                 }
9113                 WARN_ON(ret > 0);
9114
9115                 /*
9116                  * unlock our path, this is safe because only this
9117                  * function is allowed to delete this snapshot
9118                  */
9119                 btrfs_unlock_up_safe(path, 0);
9120
9121                 level = btrfs_header_level(root->node);
9122                 while (1) {
9123                         btrfs_tree_lock(path->nodes[level]);
9124                         btrfs_set_lock_blocking(path->nodes[level]);
9125                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9126
9127                         ret = btrfs_lookup_extent_info(trans, fs_info,
9128                                                 path->nodes[level]->start,
9129                                                 level, 1, &wc->refs[level],
9130                                                 &wc->flags[level]);
9131                         if (ret < 0) {
9132                                 err = ret;
9133                                 goto out_end_trans;
9134                         }
9135                         BUG_ON(wc->refs[level] == 0);
9136
9137                         if (level == root_item->drop_level)
9138                                 break;
9139
9140                         btrfs_tree_unlock(path->nodes[level]);
9141                         path->locks[level] = 0;
9142                         WARN_ON(wc->refs[level] != 1);
9143                         level--;
9144                 }
9145         }
9146
9147         wc->level = level;
9148         wc->shared_level = -1;
9149         wc->stage = DROP_REFERENCE;
9150         wc->update_ref = update_ref;
9151         wc->keep_locks = 0;
9152         wc->for_reloc = for_reloc;
9153         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9154
9155         while (1) {
9156
9157                 ret = walk_down_tree(trans, root, path, wc);
9158                 if (ret < 0) {
9159                         err = ret;
9160                         break;
9161                 }
9162
9163                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9164                 if (ret < 0) {
9165                         err = ret;
9166                         break;
9167                 }
9168
9169                 if (ret > 0) {
9170                         BUG_ON(wc->stage != DROP_REFERENCE);
9171                         break;
9172                 }
9173
9174                 if (wc->stage == DROP_REFERENCE) {
9175                         level = wc->level;
9176                         btrfs_node_key(path->nodes[level],
9177                                        &root_item->drop_progress,
9178                                        path->slots[level]);
9179                         root_item->drop_level = level;
9180                 }
9181
9182                 BUG_ON(wc->level == 0);
9183                 if (btrfs_should_end_transaction(trans) ||
9184                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9185                         ret = btrfs_update_root(trans, tree_root,
9186                                                 &root->root_key,
9187                                                 root_item);
9188                         if (ret) {
9189                                 btrfs_abort_transaction(trans, ret);
9190                                 err = ret;
9191                                 goto out_end_trans;
9192                         }
9193
9194                         btrfs_end_transaction_throttle(trans);
9195                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9196                                 btrfs_debug(fs_info,
9197                                             "drop snapshot early exit");
9198                                 err = -EAGAIN;
9199                                 goto out_free;
9200                         }
9201
9202                         trans = btrfs_start_transaction(tree_root, 0);
9203                         if (IS_ERR(trans)) {
9204                                 err = PTR_ERR(trans);
9205                                 goto out_free;
9206                         }
9207                         if (block_rsv)
9208                                 trans->block_rsv = block_rsv;
9209                 }
9210         }
9211         btrfs_release_path(path);
9212         if (err)
9213                 goto out_end_trans;
9214
9215         ret = btrfs_del_root(trans, fs_info, &root->root_key);
9216         if (ret) {
9217                 btrfs_abort_transaction(trans, ret);
9218                 err = ret;
9219                 goto out_end_trans;
9220         }
9221
9222         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9223                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9224                                       NULL, NULL);
9225                 if (ret < 0) {
9226                         btrfs_abort_transaction(trans, ret);
9227                         err = ret;
9228                         goto out_end_trans;
9229                 } else if (ret > 0) {
9230                         /* if we fail to delete the orphan item this time
9231                          * around, it'll get picked up the next time.
9232                          *
9233                          * The most common failure here is just -ENOENT.
9234                          */
9235                         btrfs_del_orphan_item(trans, tree_root,
9236                                               root->root_key.objectid);
9237                 }
9238         }
9239
9240         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9241                 btrfs_add_dropped_root(trans, root);
9242         } else {
9243                 free_extent_buffer(root->node);
9244                 free_extent_buffer(root->commit_root);
9245                 btrfs_put_fs_root(root);
9246         }
9247         root_dropped = true;
9248 out_end_trans:
9249         btrfs_end_transaction_throttle(trans);
9250 out_free:
9251         kfree(wc);
9252         btrfs_free_path(path);
9253 out:
9254         /*
9255          * So if we need to stop dropping the snapshot for whatever reason we
9256          * need to make sure to add it back to the dead root list so that we
9257          * keep trying to do the work later.  This also cleans up roots if we
9258          * don't have it in the radix (like when we recover after a power fail
9259          * or unmount) so we don't leak memory.
9260          */
9261         if (!for_reloc && !root_dropped)
9262                 btrfs_add_dead_root(root);
9263         if (err && err != -EAGAIN)
9264                 btrfs_handle_fs_error(fs_info, err, NULL);
9265         return err;
9266 }
9267
9268 /*
9269  * drop subtree rooted at tree block 'node'.
9270  *
9271  * NOTE: this function will unlock and release tree block 'node'
9272  * only used by relocation code
9273  */
9274 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9275                         struct btrfs_root *root,
9276                         struct extent_buffer *node,
9277                         struct extent_buffer *parent)
9278 {
9279         struct btrfs_fs_info *fs_info = root->fs_info;
9280         struct btrfs_path *path;
9281         struct walk_control *wc;
9282         int level;
9283         int parent_level;
9284         int ret = 0;
9285         int wret;
9286
9287         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9288
9289         path = btrfs_alloc_path();
9290         if (!path)
9291                 return -ENOMEM;
9292
9293         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9294         if (!wc) {
9295                 btrfs_free_path(path);
9296                 return -ENOMEM;
9297         }
9298
9299         btrfs_assert_tree_locked(parent);
9300         parent_level = btrfs_header_level(parent);
9301         extent_buffer_get(parent);
9302         path->nodes[parent_level] = parent;
9303         path->slots[parent_level] = btrfs_header_nritems(parent);
9304
9305         btrfs_assert_tree_locked(node);
9306         level = btrfs_header_level(node);
9307         path->nodes[level] = node;
9308         path->slots[level] = 0;
9309         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9310
9311         wc->refs[parent_level] = 1;
9312         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9313         wc->level = level;
9314         wc->shared_level = -1;
9315         wc->stage = DROP_REFERENCE;
9316         wc->update_ref = 0;
9317         wc->keep_locks = 1;
9318         wc->for_reloc = 1;
9319         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9320
9321         while (1) {
9322                 wret = walk_down_tree(trans, root, path, wc);
9323                 if (wret < 0) {
9324                         ret = wret;
9325                         break;
9326                 }
9327
9328                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9329                 if (wret < 0)
9330                         ret = wret;
9331                 if (wret != 0)
9332                         break;
9333         }
9334
9335         kfree(wc);
9336         btrfs_free_path(path);
9337         return ret;
9338 }
9339
9340 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9341 {
9342         u64 num_devices;
9343         u64 stripped;
9344
9345         /*
9346          * if restripe for this chunk_type is on pick target profile and
9347          * return, otherwise do the usual balance
9348          */
9349         stripped = get_restripe_target(fs_info, flags);
9350         if (stripped)
9351                 return extended_to_chunk(stripped);
9352
9353         num_devices = fs_info->fs_devices->rw_devices;
9354
9355         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9356                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9357                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9358
9359         if (num_devices == 1) {
9360                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9361                 stripped = flags & ~stripped;
9362
9363                 /* turn raid0 into single device chunks */
9364                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9365                         return stripped;
9366
9367                 /* turn mirroring into duplication */
9368                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9369                              BTRFS_BLOCK_GROUP_RAID10))
9370                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9371         } else {
9372                 /* they already had raid on here, just return */
9373                 if (flags & stripped)
9374                         return flags;
9375
9376                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9377                 stripped = flags & ~stripped;
9378
9379                 /* switch duplicated blocks with raid1 */
9380                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9381                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9382
9383                 /* this is drive concat, leave it alone */
9384         }
9385
9386         return flags;
9387 }
9388
9389 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9390 {
9391         struct btrfs_space_info *sinfo = cache->space_info;
9392         u64 num_bytes;
9393         u64 min_allocable_bytes;
9394         int ret = -ENOSPC;
9395
9396         /*
9397          * We need some metadata space and system metadata space for
9398          * allocating chunks in some corner cases until we force to set
9399          * it to be readonly.
9400          */
9401         if ((sinfo->flags &
9402              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9403             !force)
9404                 min_allocable_bytes = SZ_1M;
9405         else
9406                 min_allocable_bytes = 0;
9407
9408         spin_lock(&sinfo->lock);
9409         spin_lock(&cache->lock);
9410
9411         if (cache->ro) {
9412                 cache->ro++;
9413                 ret = 0;
9414                 goto out;
9415         }
9416
9417         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9418                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9419
9420         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9421             min_allocable_bytes <= sinfo->total_bytes) {
9422                 sinfo->bytes_readonly += num_bytes;
9423                 cache->ro++;
9424                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9425                 ret = 0;
9426         }
9427 out:
9428         spin_unlock(&cache->lock);
9429         spin_unlock(&sinfo->lock);
9430         return ret;
9431 }
9432
9433 int btrfs_inc_block_group_ro(struct btrfs_fs_info *fs_info,
9434                              struct btrfs_block_group_cache *cache)
9435
9436 {
9437         struct btrfs_trans_handle *trans;
9438         u64 alloc_flags;
9439         int ret;
9440
9441 again:
9442         trans = btrfs_join_transaction(fs_info->extent_root);
9443         if (IS_ERR(trans))
9444                 return PTR_ERR(trans);
9445
9446         /*
9447          * we're not allowed to set block groups readonly after the dirty
9448          * block groups cache has started writing.  If it already started,
9449          * back off and let this transaction commit
9450          */
9451         mutex_lock(&fs_info->ro_block_group_mutex);
9452         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9453                 u64 transid = trans->transid;
9454
9455                 mutex_unlock(&fs_info->ro_block_group_mutex);
9456                 btrfs_end_transaction(trans);
9457
9458                 ret = btrfs_wait_for_commit(fs_info, transid);
9459                 if (ret)
9460                         return ret;
9461                 goto again;
9462         }
9463
9464         /*
9465          * if we are changing raid levels, try to allocate a corresponding
9466          * block group with the new raid level.
9467          */
9468         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9469         if (alloc_flags != cache->flags) {
9470                 ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9471                                      CHUNK_ALLOC_FORCE);
9472                 /*
9473                  * ENOSPC is allowed here, we may have enough space
9474                  * already allocated at the new raid level to
9475                  * carry on
9476                  */
9477                 if (ret == -ENOSPC)
9478                         ret = 0;
9479                 if (ret < 0)
9480                         goto out;
9481         }
9482
9483         ret = inc_block_group_ro(cache, 0);
9484         if (!ret)
9485                 goto out;
9486         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9487         ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9488                              CHUNK_ALLOC_FORCE);
9489         if (ret < 0)
9490                 goto out;
9491         ret = inc_block_group_ro(cache, 0);
9492 out:
9493         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9494                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9495                 mutex_lock(&fs_info->chunk_mutex);
9496                 check_system_chunk(trans, fs_info, alloc_flags);
9497                 mutex_unlock(&fs_info->chunk_mutex);
9498         }
9499         mutex_unlock(&fs_info->ro_block_group_mutex);
9500
9501         btrfs_end_transaction(trans);
9502         return ret;
9503 }
9504
9505 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9506                             struct btrfs_fs_info *fs_info, u64 type)
9507 {
9508         u64 alloc_flags = get_alloc_profile(fs_info, type);
9509
9510         return do_chunk_alloc(trans, fs_info, alloc_flags, CHUNK_ALLOC_FORCE);
9511 }
9512
9513 /*
9514  * helper to account the unused space of all the readonly block group in the
9515  * space_info. takes mirrors into account.
9516  */
9517 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9518 {
9519         struct btrfs_block_group_cache *block_group;
9520         u64 free_bytes = 0;
9521         int factor;
9522
9523         /* It's df, we don't care if it's racy */
9524         if (list_empty(&sinfo->ro_bgs))
9525                 return 0;
9526
9527         spin_lock(&sinfo->lock);
9528         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9529                 spin_lock(&block_group->lock);
9530
9531                 if (!block_group->ro) {
9532                         spin_unlock(&block_group->lock);
9533                         continue;
9534                 }
9535
9536                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9537                                           BTRFS_BLOCK_GROUP_RAID10 |
9538                                           BTRFS_BLOCK_GROUP_DUP))
9539                         factor = 2;
9540                 else
9541                         factor = 1;
9542
9543                 free_bytes += (block_group->key.offset -
9544                                btrfs_block_group_used(&block_group->item)) *
9545                                factor;
9546
9547                 spin_unlock(&block_group->lock);
9548         }
9549         spin_unlock(&sinfo->lock);
9550
9551         return free_bytes;
9552 }
9553
9554 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9555 {
9556         struct btrfs_space_info *sinfo = cache->space_info;
9557         u64 num_bytes;
9558
9559         BUG_ON(!cache->ro);
9560
9561         spin_lock(&sinfo->lock);
9562         spin_lock(&cache->lock);
9563         if (!--cache->ro) {
9564                 num_bytes = cache->key.offset - cache->reserved -
9565                             cache->pinned - cache->bytes_super -
9566                             btrfs_block_group_used(&cache->item);
9567                 sinfo->bytes_readonly -= num_bytes;
9568                 list_del_init(&cache->ro_list);
9569         }
9570         spin_unlock(&cache->lock);
9571         spin_unlock(&sinfo->lock);
9572 }
9573
9574 /*
9575  * checks to see if its even possible to relocate this block group.
9576  *
9577  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9578  * ok to go ahead and try.
9579  */
9580 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9581 {
9582         struct btrfs_root *root = fs_info->extent_root;
9583         struct btrfs_block_group_cache *block_group;
9584         struct btrfs_space_info *space_info;
9585         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9586         struct btrfs_device *device;
9587         struct btrfs_trans_handle *trans;
9588         u64 min_free;
9589         u64 dev_min = 1;
9590         u64 dev_nr = 0;
9591         u64 target;
9592         int debug;
9593         int index;
9594         int full = 0;
9595         int ret = 0;
9596
9597         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9598
9599         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9600
9601         /* odd, couldn't find the block group, leave it alone */
9602         if (!block_group) {
9603                 if (debug)
9604                         btrfs_warn(fs_info,
9605                                    "can't find block group for bytenr %llu",
9606                                    bytenr);
9607                 return -1;
9608         }
9609
9610         min_free = btrfs_block_group_used(&block_group->item);
9611
9612         /* no bytes used, we're good */
9613         if (!min_free)
9614                 goto out;
9615
9616         space_info = block_group->space_info;
9617         spin_lock(&space_info->lock);
9618
9619         full = space_info->full;
9620
9621         /*
9622          * if this is the last block group we have in this space, we can't
9623          * relocate it unless we're able to allocate a new chunk below.
9624          *
9625          * Otherwise, we need to make sure we have room in the space to handle
9626          * all of the extents from this block group.  If we can, we're good
9627          */
9628         if ((space_info->total_bytes != block_group->key.offset) &&
9629             (btrfs_space_info_used(space_info, false) + min_free <
9630              space_info->total_bytes)) {
9631                 spin_unlock(&space_info->lock);
9632                 goto out;
9633         }
9634         spin_unlock(&space_info->lock);
9635
9636         /*
9637          * ok we don't have enough space, but maybe we have free space on our
9638          * devices to allocate new chunks for relocation, so loop through our
9639          * alloc devices and guess if we have enough space.  if this block
9640          * group is going to be restriped, run checks against the target
9641          * profile instead of the current one.
9642          */
9643         ret = -1;
9644
9645         /*
9646          * index:
9647          *      0: raid10
9648          *      1: raid1
9649          *      2: dup
9650          *      3: raid0
9651          *      4: single
9652          */
9653         target = get_restripe_target(fs_info, block_group->flags);
9654         if (target) {
9655                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9656         } else {
9657                 /*
9658                  * this is just a balance, so if we were marked as full
9659                  * we know there is no space for a new chunk
9660                  */
9661                 if (full) {
9662                         if (debug)
9663                                 btrfs_warn(fs_info,
9664                                            "no space to alloc new chunk for block group %llu",
9665                                            block_group->key.objectid);
9666                         goto out;
9667                 }
9668
9669                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9670         }
9671
9672         if (index == BTRFS_RAID_RAID10) {
9673                 dev_min = 4;
9674                 /* Divide by 2 */
9675                 min_free >>= 1;
9676         } else if (index == BTRFS_RAID_RAID1) {
9677                 dev_min = 2;
9678         } else if (index == BTRFS_RAID_DUP) {
9679                 /* Multiply by 2 */
9680                 min_free <<= 1;
9681         } else if (index == BTRFS_RAID_RAID0) {
9682                 dev_min = fs_devices->rw_devices;
9683                 min_free = div64_u64(min_free, dev_min);
9684         }
9685
9686         /* We need to do this so that we can look at pending chunks */
9687         trans = btrfs_join_transaction(root);
9688         if (IS_ERR(trans)) {
9689                 ret = PTR_ERR(trans);
9690                 goto out;
9691         }
9692
9693         mutex_lock(&fs_info->chunk_mutex);
9694         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9695                 u64 dev_offset;
9696
9697                 /*
9698                  * check to make sure we can actually find a chunk with enough
9699                  * space to fit our block group in.
9700                  */
9701                 if (device->total_bytes > device->bytes_used + min_free &&
9702                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9703                         ret = find_free_dev_extent(trans, device, min_free,
9704                                                    &dev_offset, NULL);
9705                         if (!ret)
9706                                 dev_nr++;
9707
9708                         if (dev_nr >= dev_min)
9709                                 break;
9710
9711                         ret = -1;
9712                 }
9713         }
9714         if (debug && ret == -1)
9715                 btrfs_warn(fs_info,
9716                            "no space to allocate a new chunk for block group %llu",
9717                            block_group->key.objectid);
9718         mutex_unlock(&fs_info->chunk_mutex);
9719         btrfs_end_transaction(trans);
9720 out:
9721         btrfs_put_block_group(block_group);
9722         return ret;
9723 }
9724
9725 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9726                                   struct btrfs_path *path,
9727                                   struct btrfs_key *key)
9728 {
9729         struct btrfs_root *root = fs_info->extent_root;
9730         int ret = 0;
9731         struct btrfs_key found_key;
9732         struct extent_buffer *leaf;
9733         int slot;
9734
9735         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9736         if (ret < 0)
9737                 goto out;
9738
9739         while (1) {
9740                 slot = path->slots[0];
9741                 leaf = path->nodes[0];
9742                 if (slot >= btrfs_header_nritems(leaf)) {
9743                         ret = btrfs_next_leaf(root, path);
9744                         if (ret == 0)
9745                                 continue;
9746                         if (ret < 0)
9747                                 goto out;
9748                         break;
9749                 }
9750                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9751
9752                 if (found_key.objectid >= key->objectid &&
9753                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9754                         struct extent_map_tree *em_tree;
9755                         struct extent_map *em;
9756
9757                         em_tree = &root->fs_info->mapping_tree.map_tree;
9758                         read_lock(&em_tree->lock);
9759                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9760                                                    found_key.offset);
9761                         read_unlock(&em_tree->lock);
9762                         if (!em) {
9763                                 btrfs_err(fs_info,
9764                         "logical %llu len %llu found bg but no related chunk",
9765                                           found_key.objectid, found_key.offset);
9766                                 ret = -ENOENT;
9767                         } else {
9768                                 ret = 0;
9769                         }
9770                         free_extent_map(em);
9771                         goto out;
9772                 }
9773                 path->slots[0]++;
9774         }
9775 out:
9776         return ret;
9777 }
9778
9779 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9780 {
9781         struct btrfs_block_group_cache *block_group;
9782         u64 last = 0;
9783
9784         while (1) {
9785                 struct inode *inode;
9786
9787                 block_group = btrfs_lookup_first_block_group(info, last);
9788                 while (block_group) {
9789                         spin_lock(&block_group->lock);
9790                         if (block_group->iref)
9791                                 break;
9792                         spin_unlock(&block_group->lock);
9793                         block_group = next_block_group(info, block_group);
9794                 }
9795                 if (!block_group) {
9796                         if (last == 0)
9797                                 break;
9798                         last = 0;
9799                         continue;
9800                 }
9801
9802                 inode = block_group->inode;
9803                 block_group->iref = 0;
9804                 block_group->inode = NULL;
9805                 spin_unlock(&block_group->lock);
9806                 ASSERT(block_group->io_ctl.inode == NULL);
9807                 iput(inode);
9808                 last = block_group->key.objectid + block_group->key.offset;
9809                 btrfs_put_block_group(block_group);
9810         }
9811 }
9812
9813 /*
9814  * Must be called only after stopping all workers, since we could have block
9815  * group caching kthreads running, and therefore they could race with us if we
9816  * freed the block groups before stopping them.
9817  */
9818 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9819 {
9820         struct btrfs_block_group_cache *block_group;
9821         struct btrfs_space_info *space_info;
9822         struct btrfs_caching_control *caching_ctl;
9823         struct rb_node *n;
9824
9825         down_write(&info->commit_root_sem);
9826         while (!list_empty(&info->caching_block_groups)) {
9827                 caching_ctl = list_entry(info->caching_block_groups.next,
9828                                          struct btrfs_caching_control, list);
9829                 list_del(&caching_ctl->list);
9830                 put_caching_control(caching_ctl);
9831         }
9832         up_write(&info->commit_root_sem);
9833
9834         spin_lock(&info->unused_bgs_lock);
9835         while (!list_empty(&info->unused_bgs)) {
9836                 block_group = list_first_entry(&info->unused_bgs,
9837                                                struct btrfs_block_group_cache,
9838                                                bg_list);
9839                 list_del_init(&block_group->bg_list);
9840                 btrfs_put_block_group(block_group);
9841         }
9842         spin_unlock(&info->unused_bgs_lock);
9843
9844         spin_lock(&info->block_group_cache_lock);
9845         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9846                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9847                                        cache_node);
9848                 rb_erase(&block_group->cache_node,
9849                          &info->block_group_cache_tree);
9850                 RB_CLEAR_NODE(&block_group->cache_node);
9851                 spin_unlock(&info->block_group_cache_lock);
9852
9853                 down_write(&block_group->space_info->groups_sem);
9854                 list_del(&block_group->list);
9855                 up_write(&block_group->space_info->groups_sem);
9856
9857                 /*
9858                  * We haven't cached this block group, which means we could
9859                  * possibly have excluded extents on this block group.
9860                  */
9861                 if (block_group->cached == BTRFS_CACHE_NO ||
9862                     block_group->cached == BTRFS_CACHE_ERROR)
9863                         free_excluded_extents(info, block_group);
9864
9865                 btrfs_remove_free_space_cache(block_group);
9866                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9867                 ASSERT(list_empty(&block_group->dirty_list));
9868                 ASSERT(list_empty(&block_group->io_list));
9869                 ASSERT(list_empty(&block_group->bg_list));
9870                 ASSERT(atomic_read(&block_group->count) == 1);
9871                 btrfs_put_block_group(block_group);
9872
9873                 spin_lock(&info->block_group_cache_lock);
9874         }
9875         spin_unlock(&info->block_group_cache_lock);
9876
9877         /* now that all the block groups are freed, go through and
9878          * free all the space_info structs.  This is only called during
9879          * the final stages of unmount, and so we know nobody is
9880          * using them.  We call synchronize_rcu() once before we start,
9881          * just to be on the safe side.
9882          */
9883         synchronize_rcu();
9884
9885         release_global_block_rsv(info);
9886
9887         while (!list_empty(&info->space_info)) {
9888                 int i;
9889
9890                 space_info = list_entry(info->space_info.next,
9891                                         struct btrfs_space_info,
9892                                         list);
9893
9894                 /*
9895                  * Do not hide this behind enospc_debug, this is actually
9896                  * important and indicates a real bug if this happens.
9897                  */
9898                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9899                             space_info->bytes_reserved > 0 ||
9900                             space_info->bytes_may_use > 0))
9901                         dump_space_info(info, space_info, 0, 0);
9902                 list_del(&space_info->list);
9903                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9904                         struct kobject *kobj;
9905                         kobj = space_info->block_group_kobjs[i];
9906                         space_info->block_group_kobjs[i] = NULL;
9907                         if (kobj) {
9908                                 kobject_del(kobj);
9909                                 kobject_put(kobj);
9910                         }
9911                 }
9912                 kobject_del(&space_info->kobj);
9913                 kobject_put(&space_info->kobj);
9914         }
9915         return 0;
9916 }
9917
9918 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9919 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9920 {
9921         struct btrfs_space_info *space_info;
9922         struct raid_kobject *rkobj;
9923         LIST_HEAD(list);
9924         int index;
9925         int ret = 0;
9926
9927         spin_lock(&fs_info->pending_raid_kobjs_lock);
9928         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9929         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9930
9931         list_for_each_entry(rkobj, &list, list) {
9932                 space_info = __find_space_info(fs_info, rkobj->flags);
9933                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9934
9935                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9936                                   "%s", get_raid_name(index));
9937                 if (ret) {
9938                         kobject_put(&rkobj->kobj);
9939                         break;
9940                 }
9941         }
9942         if (ret)
9943                 btrfs_warn(fs_info,
9944                            "failed to add kobject for block cache, ignoring");
9945 }
9946
9947 static void link_block_group(struct btrfs_block_group_cache *cache)
9948 {
9949         struct btrfs_space_info *space_info = cache->space_info;
9950         struct btrfs_fs_info *fs_info = cache->fs_info;
9951         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9952         bool first = false;
9953
9954         down_write(&space_info->groups_sem);
9955         if (list_empty(&space_info->block_groups[index]))
9956                 first = true;
9957         list_add_tail(&cache->list, &space_info->block_groups[index]);
9958         up_write(&space_info->groups_sem);
9959
9960         if (first) {
9961                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9962                 if (!rkobj) {
9963                         btrfs_warn(cache->fs_info,
9964                                 "couldn't alloc memory for raid level kobject");
9965                         return;
9966                 }
9967                 rkobj->flags = cache->flags;
9968                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9969
9970                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9971                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9972                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9973                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9974         }
9975 }
9976
9977 static struct btrfs_block_group_cache *
9978 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9979                                u64 start, u64 size)
9980 {
9981         struct btrfs_block_group_cache *cache;
9982
9983         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9984         if (!cache)
9985                 return NULL;
9986
9987         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9988                                         GFP_NOFS);
9989         if (!cache->free_space_ctl) {
9990                 kfree(cache);
9991                 return NULL;
9992         }
9993
9994         cache->key.objectid = start;
9995         cache->key.offset = size;
9996         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9997
9998         cache->fs_info = fs_info;
9999         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
10000         set_free_space_tree_thresholds(cache);
10001
10002         atomic_set(&cache->count, 1);
10003         spin_lock_init(&cache->lock);
10004         init_rwsem(&cache->data_rwsem);
10005         INIT_LIST_HEAD(&cache->list);
10006         INIT_LIST_HEAD(&cache->cluster_list);
10007         INIT_LIST_HEAD(&cache->bg_list);
10008         INIT_LIST_HEAD(&cache->ro_list);
10009         INIT_LIST_HEAD(&cache->dirty_list);
10010         INIT_LIST_HEAD(&cache->io_list);
10011         btrfs_init_free_space_ctl(cache);
10012         atomic_set(&cache->trimming, 0);
10013         mutex_init(&cache->free_space_lock);
10014         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
10015
10016         return cache;
10017 }
10018
10019 int btrfs_read_block_groups(struct btrfs_fs_info *info)
10020 {
10021         struct btrfs_path *path;
10022         int ret;
10023         struct btrfs_block_group_cache *cache;
10024         struct btrfs_space_info *space_info;
10025         struct btrfs_key key;
10026         struct btrfs_key found_key;
10027         struct extent_buffer *leaf;
10028         int need_clear = 0;
10029         u64 cache_gen;
10030         u64 feature;
10031         int mixed;
10032
10033         feature = btrfs_super_incompat_flags(info->super_copy);
10034         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10035
10036         key.objectid = 0;
10037         key.offset = 0;
10038         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10039         path = btrfs_alloc_path();
10040         if (!path)
10041                 return -ENOMEM;
10042         path->reada = READA_FORWARD;
10043
10044         cache_gen = btrfs_super_cache_generation(info->super_copy);
10045         if (btrfs_test_opt(info, SPACE_CACHE) &&
10046             btrfs_super_generation(info->super_copy) != cache_gen)
10047                 need_clear = 1;
10048         if (btrfs_test_opt(info, CLEAR_CACHE))
10049                 need_clear = 1;
10050
10051         while (1) {
10052                 ret = find_first_block_group(info, path, &key);
10053                 if (ret > 0)
10054                         break;
10055                 if (ret != 0)
10056                         goto error;
10057
10058                 leaf = path->nodes[0];
10059                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10060
10061                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
10062                                                        found_key.offset);
10063                 if (!cache) {
10064                         ret = -ENOMEM;
10065                         goto error;
10066                 }
10067
10068                 if (need_clear) {
10069                         /*
10070                          * When we mount with old space cache, we need to
10071                          * set BTRFS_DC_CLEAR and set dirty flag.
10072                          *
10073                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10074                          *    truncate the old free space cache inode and
10075                          *    setup a new one.
10076                          * b) Setting 'dirty flag' makes sure that we flush
10077                          *    the new space cache info onto disk.
10078                          */
10079                         if (btrfs_test_opt(info, SPACE_CACHE))
10080                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10081                 }
10082
10083                 read_extent_buffer(leaf, &cache->item,
10084                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10085                                    sizeof(cache->item));
10086                 cache->flags = btrfs_block_group_flags(&cache->item);
10087                 if (!mixed &&
10088                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10089                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10090                         btrfs_err(info,
10091 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10092                                   cache->key.objectid);
10093                         ret = -EINVAL;
10094                         goto error;
10095                 }
10096
10097                 key.objectid = found_key.objectid + found_key.offset;
10098                 btrfs_release_path(path);
10099
10100                 /*
10101                  * We need to exclude the super stripes now so that the space
10102                  * info has super bytes accounted for, otherwise we'll think
10103                  * we have more space than we actually do.
10104                  */
10105                 ret = exclude_super_stripes(info, cache);
10106                 if (ret) {
10107                         /*
10108                          * We may have excluded something, so call this just in
10109                          * case.
10110                          */
10111                         free_excluded_extents(info, cache);
10112                         btrfs_put_block_group(cache);
10113                         goto error;
10114                 }
10115
10116                 /*
10117                  * check for two cases, either we are full, and therefore
10118                  * don't need to bother with the caching work since we won't
10119                  * find any space, or we are empty, and we can just add all
10120                  * the space in and be done with it.  This saves us _alot_ of
10121                  * time, particularly in the full case.
10122                  */
10123                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10124                         cache->last_byte_to_unpin = (u64)-1;
10125                         cache->cached = BTRFS_CACHE_FINISHED;
10126                         free_excluded_extents(info, cache);
10127                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10128                         cache->last_byte_to_unpin = (u64)-1;
10129                         cache->cached = BTRFS_CACHE_FINISHED;
10130                         add_new_free_space(cache, info,
10131                                            found_key.objectid,
10132                                            found_key.objectid +
10133                                            found_key.offset);
10134                         free_excluded_extents(info, cache);
10135                 }
10136
10137                 ret = btrfs_add_block_group_cache(info, cache);
10138                 if (ret) {
10139                         btrfs_remove_free_space_cache(cache);
10140                         btrfs_put_block_group(cache);
10141                         goto error;
10142                 }
10143
10144                 trace_btrfs_add_block_group(info, cache, 0);
10145                 update_space_info(info, cache->flags, found_key.offset,
10146                                   btrfs_block_group_used(&cache->item),
10147                                   cache->bytes_super, &space_info);
10148
10149                 cache->space_info = space_info;
10150
10151                 link_block_group(cache);
10152
10153                 set_avail_alloc_bits(info, cache->flags);
10154                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10155                         inc_block_group_ro(cache, 1);
10156                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10157                         spin_lock(&info->unused_bgs_lock);
10158                         /* Should always be true but just in case. */
10159                         if (list_empty(&cache->bg_list)) {
10160                                 btrfs_get_block_group(cache);
10161                                 list_add_tail(&cache->bg_list,
10162                                               &info->unused_bgs);
10163                         }
10164                         spin_unlock(&info->unused_bgs_lock);
10165                 }
10166         }
10167
10168         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10169                 if (!(get_alloc_profile(info, space_info->flags) &
10170                       (BTRFS_BLOCK_GROUP_RAID10 |
10171                        BTRFS_BLOCK_GROUP_RAID1 |
10172                        BTRFS_BLOCK_GROUP_RAID5 |
10173                        BTRFS_BLOCK_GROUP_RAID6 |
10174                        BTRFS_BLOCK_GROUP_DUP)))
10175                         continue;
10176                 /*
10177                  * avoid allocating from un-mirrored block group if there are
10178                  * mirrored block groups.
10179                  */
10180                 list_for_each_entry(cache,
10181                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10182                                 list)
10183                         inc_block_group_ro(cache, 1);
10184                 list_for_each_entry(cache,
10185                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10186                                 list)
10187                         inc_block_group_ro(cache, 1);
10188         }
10189
10190         btrfs_add_raid_kobjects(info);
10191         init_global_block_rsv(info);
10192         ret = 0;
10193 error:
10194         btrfs_free_path(path);
10195         return ret;
10196 }
10197
10198 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10199 {
10200         struct btrfs_fs_info *fs_info = trans->fs_info;
10201         struct btrfs_block_group_cache *block_group, *tmp;
10202         struct btrfs_root *extent_root = fs_info->extent_root;
10203         struct btrfs_block_group_item item;
10204         struct btrfs_key key;
10205         int ret = 0;
10206         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10207
10208         trans->can_flush_pending_bgs = false;
10209         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10210                 if (ret)
10211                         goto next;
10212
10213                 spin_lock(&block_group->lock);
10214                 memcpy(&item, &block_group->item, sizeof(item));
10215                 memcpy(&key, &block_group->key, sizeof(key));
10216                 spin_unlock(&block_group->lock);
10217
10218                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10219                                         sizeof(item));
10220                 if (ret)
10221                         btrfs_abort_transaction(trans, ret);
10222                 ret = btrfs_finish_chunk_alloc(trans, fs_info, key.objectid,
10223                                                key.offset);
10224                 if (ret)
10225                         btrfs_abort_transaction(trans, ret);
10226                 add_block_group_free_space(trans, fs_info, block_group);
10227                 /* already aborted the transaction if it failed. */
10228 next:
10229                 list_del_init(&block_group->bg_list);
10230         }
10231         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10232 }
10233
10234 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10235                            struct btrfs_fs_info *fs_info, u64 bytes_used,
10236                            u64 type, u64 chunk_offset, u64 size)
10237 {
10238         struct btrfs_block_group_cache *cache;
10239         int ret;
10240
10241         btrfs_set_log_full_commit(fs_info, trans);
10242
10243         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10244         if (!cache)
10245                 return -ENOMEM;
10246
10247         btrfs_set_block_group_used(&cache->item, bytes_used);
10248         btrfs_set_block_group_chunk_objectid(&cache->item,
10249                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10250         btrfs_set_block_group_flags(&cache->item, type);
10251
10252         cache->flags = type;
10253         cache->last_byte_to_unpin = (u64)-1;
10254         cache->cached = BTRFS_CACHE_FINISHED;
10255         cache->needs_free_space = 1;
10256         ret = exclude_super_stripes(fs_info, cache);
10257         if (ret) {
10258                 /*
10259                  * We may have excluded something, so call this just in
10260                  * case.
10261                  */
10262                 free_excluded_extents(fs_info, cache);
10263                 btrfs_put_block_group(cache);
10264                 return ret;
10265         }
10266
10267         add_new_free_space(cache, fs_info, chunk_offset, chunk_offset + size);
10268
10269         free_excluded_extents(fs_info, cache);
10270
10271 #ifdef CONFIG_BTRFS_DEBUG
10272         if (btrfs_should_fragment_free_space(cache)) {
10273                 u64 new_bytes_used = size - bytes_used;
10274
10275                 bytes_used += new_bytes_used >> 1;
10276                 fragment_free_space(cache);
10277         }
10278 #endif
10279         /*
10280          * Ensure the corresponding space_info object is created and
10281          * assigned to our block group. We want our bg to be added to the rbtree
10282          * with its ->space_info set.
10283          */
10284         cache->space_info = __find_space_info(fs_info, cache->flags);
10285         ASSERT(cache->space_info);
10286
10287         ret = btrfs_add_block_group_cache(fs_info, cache);
10288         if (ret) {
10289                 btrfs_remove_free_space_cache(cache);
10290                 btrfs_put_block_group(cache);
10291                 return ret;
10292         }
10293
10294         /*
10295          * Now that our block group has its ->space_info set and is inserted in
10296          * the rbtree, update the space info's counters.
10297          */
10298         trace_btrfs_add_block_group(fs_info, cache, 1);
10299         update_space_info(fs_info, cache->flags, size, bytes_used,
10300                                 cache->bytes_super, &cache->space_info);
10301         update_global_block_rsv(fs_info);
10302
10303         link_block_group(cache);
10304
10305         list_add_tail(&cache->bg_list, &trans->new_bgs);
10306
10307         set_avail_alloc_bits(fs_info, type);
10308         return 0;
10309 }
10310
10311 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10312 {
10313         u64 extra_flags = chunk_to_extended(flags) &
10314                                 BTRFS_EXTENDED_PROFILE_MASK;
10315
10316         write_seqlock(&fs_info->profiles_lock);
10317         if (flags & BTRFS_BLOCK_GROUP_DATA)
10318                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10319         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10320                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10321         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10322                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10323         write_sequnlock(&fs_info->profiles_lock);
10324 }
10325
10326 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10327                              struct btrfs_fs_info *fs_info, u64 group_start,
10328                              struct extent_map *em)
10329 {
10330         struct btrfs_root *root = fs_info->extent_root;
10331         struct btrfs_path *path;
10332         struct btrfs_block_group_cache *block_group;
10333         struct btrfs_free_cluster *cluster;
10334         struct btrfs_root *tree_root = fs_info->tree_root;
10335         struct btrfs_key key;
10336         struct inode *inode;
10337         struct kobject *kobj = NULL;
10338         int ret;
10339         int index;
10340         int factor;
10341         struct btrfs_caching_control *caching_ctl = NULL;
10342         bool remove_em;
10343
10344         block_group = btrfs_lookup_block_group(fs_info, group_start);
10345         BUG_ON(!block_group);
10346         BUG_ON(!block_group->ro);
10347
10348         /*
10349          * Free the reserved super bytes from this block group before
10350          * remove it.
10351          */
10352         free_excluded_extents(fs_info, block_group);
10353         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10354                                   block_group->key.offset);
10355
10356         memcpy(&key, &block_group->key, sizeof(key));
10357         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10358         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10359                                   BTRFS_BLOCK_GROUP_RAID1 |
10360                                   BTRFS_BLOCK_GROUP_RAID10))
10361                 factor = 2;
10362         else
10363                 factor = 1;
10364
10365         /* make sure this block group isn't part of an allocation cluster */
10366         cluster = &fs_info->data_alloc_cluster;
10367         spin_lock(&cluster->refill_lock);
10368         btrfs_return_cluster_to_free_space(block_group, cluster);
10369         spin_unlock(&cluster->refill_lock);
10370
10371         /*
10372          * make sure this block group isn't part of a metadata
10373          * allocation cluster
10374          */
10375         cluster = &fs_info->meta_alloc_cluster;
10376         spin_lock(&cluster->refill_lock);
10377         btrfs_return_cluster_to_free_space(block_group, cluster);
10378         spin_unlock(&cluster->refill_lock);
10379
10380         path = btrfs_alloc_path();
10381         if (!path) {
10382                 ret = -ENOMEM;
10383                 goto out;
10384         }
10385
10386         /*
10387          * get the inode first so any iput calls done for the io_list
10388          * aren't the final iput (no unlinks allowed now)
10389          */
10390         inode = lookup_free_space_inode(fs_info, block_group, path);
10391
10392         mutex_lock(&trans->transaction->cache_write_mutex);
10393         /*
10394          * make sure our free spache cache IO is done before remove the
10395          * free space inode
10396          */
10397         spin_lock(&trans->transaction->dirty_bgs_lock);
10398         if (!list_empty(&block_group->io_list)) {
10399                 list_del_init(&block_group->io_list);
10400
10401                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10402
10403                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10404                 btrfs_wait_cache_io(trans, block_group, path);
10405                 btrfs_put_block_group(block_group);
10406                 spin_lock(&trans->transaction->dirty_bgs_lock);
10407         }
10408
10409         if (!list_empty(&block_group->dirty_list)) {
10410                 list_del_init(&block_group->dirty_list);
10411                 btrfs_put_block_group(block_group);
10412         }
10413         spin_unlock(&trans->transaction->dirty_bgs_lock);
10414         mutex_unlock(&trans->transaction->cache_write_mutex);
10415
10416         if (!IS_ERR(inode)) {
10417                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10418                 if (ret) {
10419                         btrfs_add_delayed_iput(inode);
10420                         goto out;
10421                 }
10422                 clear_nlink(inode);
10423                 /* One for the block groups ref */
10424                 spin_lock(&block_group->lock);
10425                 if (block_group->iref) {
10426                         block_group->iref = 0;
10427                         block_group->inode = NULL;
10428                         spin_unlock(&block_group->lock);
10429                         iput(inode);
10430                 } else {
10431                         spin_unlock(&block_group->lock);
10432                 }
10433                 /* One for our lookup ref */
10434                 btrfs_add_delayed_iput(inode);
10435         }
10436
10437         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10438         key.offset = block_group->key.objectid;
10439         key.type = 0;
10440
10441         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10442         if (ret < 0)
10443                 goto out;
10444         if (ret > 0)
10445                 btrfs_release_path(path);
10446         if (ret == 0) {
10447                 ret = btrfs_del_item(trans, tree_root, path);
10448                 if (ret)
10449                         goto out;
10450                 btrfs_release_path(path);
10451         }
10452
10453         spin_lock(&fs_info->block_group_cache_lock);
10454         rb_erase(&block_group->cache_node,
10455                  &fs_info->block_group_cache_tree);
10456         RB_CLEAR_NODE(&block_group->cache_node);
10457
10458         if (fs_info->first_logical_byte == block_group->key.objectid)
10459                 fs_info->first_logical_byte = (u64)-1;
10460         spin_unlock(&fs_info->block_group_cache_lock);
10461
10462         down_write(&block_group->space_info->groups_sem);
10463         /*
10464          * we must use list_del_init so people can check to see if they
10465          * are still on the list after taking the semaphore
10466          */
10467         list_del_init(&block_group->list);
10468         if (list_empty(&block_group->space_info->block_groups[index])) {
10469                 kobj = block_group->space_info->block_group_kobjs[index];
10470                 block_group->space_info->block_group_kobjs[index] = NULL;
10471                 clear_avail_alloc_bits(fs_info, block_group->flags);
10472         }
10473         up_write(&block_group->space_info->groups_sem);
10474         if (kobj) {
10475                 kobject_del(kobj);
10476                 kobject_put(kobj);
10477         }
10478
10479         if (block_group->has_caching_ctl)
10480                 caching_ctl = get_caching_control(block_group);
10481         if (block_group->cached == BTRFS_CACHE_STARTED)
10482                 wait_block_group_cache_done(block_group);
10483         if (block_group->has_caching_ctl) {
10484                 down_write(&fs_info->commit_root_sem);
10485                 if (!caching_ctl) {
10486                         struct btrfs_caching_control *ctl;
10487
10488                         list_for_each_entry(ctl,
10489                                     &fs_info->caching_block_groups, list)
10490                                 if (ctl->block_group == block_group) {
10491                                         caching_ctl = ctl;
10492                                         refcount_inc(&caching_ctl->count);
10493                                         break;
10494                                 }
10495                 }
10496                 if (caching_ctl)
10497                         list_del_init(&caching_ctl->list);
10498                 up_write(&fs_info->commit_root_sem);
10499                 if (caching_ctl) {
10500                         /* Once for the caching bgs list and once for us. */
10501                         put_caching_control(caching_ctl);
10502                         put_caching_control(caching_ctl);
10503                 }
10504         }
10505
10506         spin_lock(&trans->transaction->dirty_bgs_lock);
10507         if (!list_empty(&block_group->dirty_list)) {
10508                 WARN_ON(1);
10509         }
10510         if (!list_empty(&block_group->io_list)) {
10511                 WARN_ON(1);
10512         }
10513         spin_unlock(&trans->transaction->dirty_bgs_lock);
10514         btrfs_remove_free_space_cache(block_group);
10515
10516         spin_lock(&block_group->space_info->lock);
10517         list_del_init(&block_group->ro_list);
10518
10519         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10520                 WARN_ON(block_group->space_info->total_bytes
10521                         < block_group->key.offset);
10522                 WARN_ON(block_group->space_info->bytes_readonly
10523                         < block_group->key.offset);
10524                 WARN_ON(block_group->space_info->disk_total
10525                         < block_group->key.offset * factor);
10526         }
10527         block_group->space_info->total_bytes -= block_group->key.offset;
10528         block_group->space_info->bytes_readonly -= block_group->key.offset;
10529         block_group->space_info->disk_total -= block_group->key.offset * factor;
10530
10531         spin_unlock(&block_group->space_info->lock);
10532
10533         memcpy(&key, &block_group->key, sizeof(key));
10534
10535         mutex_lock(&fs_info->chunk_mutex);
10536         if (!list_empty(&em->list)) {
10537                 /* We're in the transaction->pending_chunks list. */
10538                 free_extent_map(em);
10539         }
10540         spin_lock(&block_group->lock);
10541         block_group->removed = 1;
10542         /*
10543          * At this point trimming can't start on this block group, because we
10544          * removed the block group from the tree fs_info->block_group_cache_tree
10545          * so no one can't find it anymore and even if someone already got this
10546          * block group before we removed it from the rbtree, they have already
10547          * incremented block_group->trimming - if they didn't, they won't find
10548          * any free space entries because we already removed them all when we
10549          * called btrfs_remove_free_space_cache().
10550          *
10551          * And we must not remove the extent map from the fs_info->mapping_tree
10552          * to prevent the same logical address range and physical device space
10553          * ranges from being reused for a new block group. This is because our
10554          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10555          * completely transactionless, so while it is trimming a range the
10556          * currently running transaction might finish and a new one start,
10557          * allowing for new block groups to be created that can reuse the same
10558          * physical device locations unless we take this special care.
10559          *
10560          * There may also be an implicit trim operation if the file system
10561          * is mounted with -odiscard. The same protections must remain
10562          * in place until the extents have been discarded completely when
10563          * the transaction commit has completed.
10564          */
10565         remove_em = (atomic_read(&block_group->trimming) == 0);
10566         /*
10567          * Make sure a trimmer task always sees the em in the pinned_chunks list
10568          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10569          * before checking block_group->removed).
10570          */
10571         if (!remove_em) {
10572                 /*
10573                  * Our em might be in trans->transaction->pending_chunks which
10574                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10575                  * and so is the fs_info->pinned_chunks list.
10576                  *
10577                  * So at this point we must be holding the chunk_mutex to avoid
10578                  * any races with chunk allocation (more specifically at
10579                  * volumes.c:contains_pending_extent()), to ensure it always
10580                  * sees the em, either in the pending_chunks list or in the
10581                  * pinned_chunks list.
10582                  */
10583                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10584         }
10585         spin_unlock(&block_group->lock);
10586
10587         if (remove_em) {
10588                 struct extent_map_tree *em_tree;
10589
10590                 em_tree = &fs_info->mapping_tree.map_tree;
10591                 write_lock(&em_tree->lock);
10592                 /*
10593                  * The em might be in the pending_chunks list, so make sure the
10594                  * chunk mutex is locked, since remove_extent_mapping() will
10595                  * delete us from that list.
10596                  */
10597                 remove_extent_mapping(em_tree, em);
10598                 write_unlock(&em_tree->lock);
10599                 /* once for the tree */
10600                 free_extent_map(em);
10601         }
10602
10603         mutex_unlock(&fs_info->chunk_mutex);
10604
10605         ret = remove_block_group_free_space(trans, fs_info, block_group);
10606         if (ret)
10607                 goto out;
10608
10609         btrfs_put_block_group(block_group);
10610         btrfs_put_block_group(block_group);
10611
10612         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10613         if (ret > 0)
10614                 ret = -EIO;
10615         if (ret < 0)
10616                 goto out;
10617
10618         ret = btrfs_del_item(trans, root, path);
10619 out:
10620         btrfs_free_path(path);
10621         return ret;
10622 }
10623
10624 struct btrfs_trans_handle *
10625 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10626                                      const u64 chunk_offset)
10627 {
10628         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10629         struct extent_map *em;
10630         struct map_lookup *map;
10631         unsigned int num_items;
10632
10633         read_lock(&em_tree->lock);
10634         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10635         read_unlock(&em_tree->lock);
10636         ASSERT(em && em->start == chunk_offset);
10637
10638         /*
10639          * We need to reserve 3 + N units from the metadata space info in order
10640          * to remove a block group (done at btrfs_remove_chunk() and at
10641          * btrfs_remove_block_group()), which are used for:
10642          *
10643          * 1 unit for adding the free space inode's orphan (located in the tree
10644          * of tree roots).
10645          * 1 unit for deleting the block group item (located in the extent
10646          * tree).
10647          * 1 unit for deleting the free space item (located in tree of tree
10648          * roots).
10649          * N units for deleting N device extent items corresponding to each
10650          * stripe (located in the device tree).
10651          *
10652          * In order to remove a block group we also need to reserve units in the
10653          * system space info in order to update the chunk tree (update one or
10654          * more device items and remove one chunk item), but this is done at
10655          * btrfs_remove_chunk() through a call to check_system_chunk().
10656          */
10657         map = em->map_lookup;
10658         num_items = 3 + map->num_stripes;
10659         free_extent_map(em);
10660
10661         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10662                                                            num_items, 1);
10663 }
10664
10665 /*
10666  * Process the unused_bgs list and remove any that don't have any allocated
10667  * space inside of them.
10668  */
10669 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10670 {
10671         struct btrfs_block_group_cache *block_group;
10672         struct btrfs_space_info *space_info;
10673         struct btrfs_trans_handle *trans;
10674         int ret = 0;
10675
10676         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10677                 return;
10678
10679         spin_lock(&fs_info->unused_bgs_lock);
10680         while (!list_empty(&fs_info->unused_bgs)) {
10681                 u64 start, end;
10682                 int trimming;
10683
10684                 block_group = list_first_entry(&fs_info->unused_bgs,
10685                                                struct btrfs_block_group_cache,
10686                                                bg_list);
10687                 list_del_init(&block_group->bg_list);
10688
10689                 space_info = block_group->space_info;
10690
10691                 if (ret || btrfs_mixed_space_info(space_info)) {
10692                         btrfs_put_block_group(block_group);
10693                         continue;
10694                 }
10695                 spin_unlock(&fs_info->unused_bgs_lock);
10696
10697                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10698
10699                 /* Don't want to race with allocators so take the groups_sem */
10700                 down_write(&space_info->groups_sem);
10701                 spin_lock(&block_group->lock);
10702                 if (block_group->reserved ||
10703                     btrfs_block_group_used(&block_group->item) ||
10704                     block_group->ro ||
10705                     list_is_singular(&block_group->list)) {
10706                         /*
10707                          * We want to bail if we made new allocations or have
10708                          * outstanding allocations in this block group.  We do
10709                          * the ro check in case balance is currently acting on
10710                          * this block group.
10711                          */
10712                         spin_unlock(&block_group->lock);
10713                         up_write(&space_info->groups_sem);
10714                         goto next;
10715                 }
10716                 spin_unlock(&block_group->lock);
10717
10718                 /* We don't want to force the issue, only flip if it's ok. */
10719                 ret = inc_block_group_ro(block_group, 0);
10720                 up_write(&space_info->groups_sem);
10721                 if (ret < 0) {
10722                         ret = 0;
10723                         goto next;
10724                 }
10725
10726                 /*
10727                  * Want to do this before we do anything else so we can recover
10728                  * properly if we fail to join the transaction.
10729                  */
10730                 trans = btrfs_start_trans_remove_block_group(fs_info,
10731                                                      block_group->key.objectid);
10732                 if (IS_ERR(trans)) {
10733                         btrfs_dec_block_group_ro(block_group);
10734                         ret = PTR_ERR(trans);
10735                         goto next;
10736                 }
10737
10738                 /*
10739                  * We could have pending pinned extents for this block group,
10740                  * just delete them, we don't care about them anymore.
10741                  */
10742                 start = block_group->key.objectid;
10743                 end = start + block_group->key.offset - 1;
10744                 /*
10745                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10746                  * btrfs_finish_extent_commit(). If we are at transaction N,
10747                  * another task might be running finish_extent_commit() for the
10748                  * previous transaction N - 1, and have seen a range belonging
10749                  * to the block group in freed_extents[] before we were able to
10750                  * clear the whole block group range from freed_extents[]. This
10751                  * means that task can lookup for the block group after we
10752                  * unpinned it from freed_extents[] and removed it, leading to
10753                  * a BUG_ON() at btrfs_unpin_extent_range().
10754                  */
10755                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10756                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10757                                   EXTENT_DIRTY);
10758                 if (ret) {
10759                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10760                         btrfs_dec_block_group_ro(block_group);
10761                         goto end_trans;
10762                 }
10763                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10764                                   EXTENT_DIRTY);
10765                 if (ret) {
10766                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10767                         btrfs_dec_block_group_ro(block_group);
10768                         goto end_trans;
10769                 }
10770                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10771
10772                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10773                 spin_lock(&space_info->lock);
10774                 spin_lock(&block_group->lock);
10775
10776                 space_info->bytes_pinned -= block_group->pinned;
10777                 space_info->bytes_readonly += block_group->pinned;
10778                 percpu_counter_add(&space_info->total_bytes_pinned,
10779                                    -block_group->pinned);
10780                 block_group->pinned = 0;
10781
10782                 spin_unlock(&block_group->lock);
10783                 spin_unlock(&space_info->lock);
10784
10785                 /* DISCARD can flip during remount */
10786                 trimming = btrfs_test_opt(fs_info, DISCARD);
10787
10788                 /* Implicit trim during transaction commit. */
10789                 if (trimming)
10790                         btrfs_get_block_group_trimming(block_group);
10791
10792                 /*
10793                  * Btrfs_remove_chunk will abort the transaction if things go
10794                  * horribly wrong.
10795                  */
10796                 ret = btrfs_remove_chunk(trans, fs_info,
10797                                          block_group->key.objectid);
10798
10799                 if (ret) {
10800                         if (trimming)
10801                                 btrfs_put_block_group_trimming(block_group);
10802                         goto end_trans;
10803                 }
10804
10805                 /*
10806                  * If we're not mounted with -odiscard, we can just forget
10807                  * about this block group. Otherwise we'll need to wait
10808                  * until transaction commit to do the actual discard.
10809                  */
10810                 if (trimming) {
10811                         spin_lock(&fs_info->unused_bgs_lock);
10812                         /*
10813                          * A concurrent scrub might have added us to the list
10814                          * fs_info->unused_bgs, so use a list_move operation
10815                          * to add the block group to the deleted_bgs list.
10816                          */
10817                         list_move(&block_group->bg_list,
10818                                   &trans->transaction->deleted_bgs);
10819                         spin_unlock(&fs_info->unused_bgs_lock);
10820                         btrfs_get_block_group(block_group);
10821                 }
10822 end_trans:
10823                 btrfs_end_transaction(trans);
10824 next:
10825                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10826                 btrfs_put_block_group(block_group);
10827                 spin_lock(&fs_info->unused_bgs_lock);
10828         }
10829         spin_unlock(&fs_info->unused_bgs_lock);
10830 }
10831
10832 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10833 {
10834         struct btrfs_space_info *space_info;
10835         struct btrfs_super_block *disk_super;
10836         u64 features;
10837         u64 flags;
10838         int mixed = 0;
10839         int ret;
10840
10841         disk_super = fs_info->super_copy;
10842         if (!btrfs_super_root(disk_super))
10843                 return -EINVAL;
10844
10845         features = btrfs_super_incompat_flags(disk_super);
10846         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10847                 mixed = 1;
10848
10849         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10850         ret = create_space_info(fs_info, flags, &space_info);
10851         if (ret)
10852                 goto out;
10853
10854         if (mixed) {
10855                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10856                 ret = create_space_info(fs_info, flags, &space_info);
10857         } else {
10858                 flags = BTRFS_BLOCK_GROUP_METADATA;
10859                 ret = create_space_info(fs_info, flags, &space_info);
10860                 if (ret)
10861                         goto out;
10862
10863                 flags = BTRFS_BLOCK_GROUP_DATA;
10864                 ret = create_space_info(fs_info, flags, &space_info);
10865         }
10866 out:
10867         return ret;
10868 }
10869
10870 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10871                                    u64 start, u64 end)
10872 {
10873         return unpin_extent_range(fs_info, start, end, false);
10874 }
10875
10876 /*
10877  * It used to be that old block groups would be left around forever.
10878  * Iterating over them would be enough to trim unused space.  Since we
10879  * now automatically remove them, we also need to iterate over unallocated
10880  * space.
10881  *
10882  * We don't want a transaction for this since the discard may take a
10883  * substantial amount of time.  We don't require that a transaction be
10884  * running, but we do need to take a running transaction into account
10885  * to ensure that we're not discarding chunks that were released in
10886  * the current transaction.
10887  *
10888  * Holding the chunks lock will prevent other threads from allocating
10889  * or releasing chunks, but it won't prevent a running transaction
10890  * from committing and releasing the memory that the pending chunks
10891  * list head uses.  For that, we need to take a reference to the
10892  * transaction.
10893  */
10894 static int btrfs_trim_free_extents(struct btrfs_device *device,
10895                                    u64 minlen, u64 *trimmed)
10896 {
10897         u64 start = 0, len = 0;
10898         int ret;
10899
10900         *trimmed = 0;
10901
10902         /* Not writeable = nothing to do. */
10903         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10904                 return 0;
10905
10906         /* No free space = nothing to do. */
10907         if (device->total_bytes <= device->bytes_used)
10908                 return 0;
10909
10910         ret = 0;
10911
10912         while (1) {
10913                 struct btrfs_fs_info *fs_info = device->fs_info;
10914                 struct btrfs_transaction *trans;
10915                 u64 bytes;
10916
10917                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10918                 if (ret)
10919                         return ret;
10920
10921                 down_read(&fs_info->commit_root_sem);
10922
10923                 spin_lock(&fs_info->trans_lock);
10924                 trans = fs_info->running_transaction;
10925                 if (trans)
10926                         refcount_inc(&trans->use_count);
10927                 spin_unlock(&fs_info->trans_lock);
10928
10929                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10930                                                  &start, &len);
10931                 if (trans)
10932                         btrfs_put_transaction(trans);
10933
10934                 if (ret) {
10935                         up_read(&fs_info->commit_root_sem);
10936                         mutex_unlock(&fs_info->chunk_mutex);
10937                         if (ret == -ENOSPC)
10938                                 ret = 0;
10939                         break;
10940                 }
10941
10942                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10943                 up_read(&fs_info->commit_root_sem);
10944                 mutex_unlock(&fs_info->chunk_mutex);
10945
10946                 if (ret)
10947                         break;
10948
10949                 start += len;
10950                 *trimmed += bytes;
10951
10952                 if (fatal_signal_pending(current)) {
10953                         ret = -ERESTARTSYS;
10954                         break;
10955                 }
10956
10957                 cond_resched();
10958         }
10959
10960         return ret;
10961 }
10962
10963 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10964 {
10965         struct btrfs_block_group_cache *cache = NULL;
10966         struct btrfs_device *device;
10967         struct list_head *devices;
10968         u64 group_trimmed;
10969         u64 start;
10970         u64 end;
10971         u64 trimmed = 0;
10972         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10973         int ret = 0;
10974
10975         /*
10976          * try to trim all FS space, our block group may start from non-zero.
10977          */
10978         if (range->len == total_bytes)
10979                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10980         else
10981                 cache = btrfs_lookup_block_group(fs_info, range->start);
10982
10983         while (cache) {
10984                 if (cache->key.objectid >= (range->start + range->len)) {
10985                         btrfs_put_block_group(cache);
10986                         break;
10987                 }
10988
10989                 start = max(range->start, cache->key.objectid);
10990                 end = min(range->start + range->len,
10991                                 cache->key.objectid + cache->key.offset);
10992
10993                 if (end - start >= range->minlen) {
10994                         if (!block_group_cache_done(cache)) {
10995                                 ret = cache_block_group(cache, 0);
10996                                 if (ret) {
10997                                         btrfs_put_block_group(cache);
10998                                         break;
10999                                 }
11000                                 ret = wait_block_group_cache_done(cache);
11001                                 if (ret) {
11002                                         btrfs_put_block_group(cache);
11003                                         break;
11004                                 }
11005                         }
11006                         ret = btrfs_trim_block_group(cache,
11007                                                      &group_trimmed,
11008                                                      start,
11009                                                      end,
11010                                                      range->minlen);
11011
11012                         trimmed += group_trimmed;
11013                         if (ret) {
11014                                 btrfs_put_block_group(cache);
11015                                 break;
11016                         }
11017                 }
11018
11019                 cache = next_block_group(fs_info, cache);
11020         }
11021
11022         mutex_lock(&fs_info->fs_devices->device_list_mutex);
11023         devices = &fs_info->fs_devices->alloc_list;
11024         list_for_each_entry(device, devices, dev_alloc_list) {
11025                 ret = btrfs_trim_free_extents(device, range->minlen,
11026                                               &group_trimmed);
11027                 if (ret)
11028                         break;
11029
11030                 trimmed += group_trimmed;
11031         }
11032         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
11033
11034         range->len = trimmed;
11035         return ret;
11036 }
11037
11038 /*
11039  * btrfs_{start,end}_write_no_snapshotting() are similar to
11040  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11041  * data into the page cache through nocow before the subvolume is snapshoted,
11042  * but flush the data into disk after the snapshot creation, or to prevent
11043  * operations while snapshotting is ongoing and that cause the snapshot to be
11044  * inconsistent (writes followed by expanding truncates for example).
11045  */
11046 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11047 {
11048         percpu_counter_dec(&root->subv_writers->counter);
11049         /*
11050          * Make sure counter is updated before we wake up waiters.
11051          */
11052         smp_mb();
11053         if (waitqueue_active(&root->subv_writers->wait))
11054                 wake_up(&root->subv_writers->wait);
11055 }
11056
11057 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11058 {
11059         if (atomic_read(&root->will_be_snapshotted))
11060                 return 0;
11061
11062         percpu_counter_inc(&root->subv_writers->counter);
11063         /*
11064          * Make sure counter is updated before we check for snapshot creation.
11065          */
11066         smp_mb();
11067         if (atomic_read(&root->will_be_snapshotted)) {
11068                 btrfs_end_write_no_snapshotting(root);
11069                 return 0;
11070         }
11071         return 1;
11072 }
11073
11074 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11075 {
11076         while (true) {
11077                 int ret;
11078
11079                 ret = btrfs_start_write_no_snapshotting(root);
11080                 if (ret)
11081                         break;
11082                 wait_on_atomic_t(&root->will_be_snapshotted, atomic_t_wait,
11083                                  TASK_UNINTERRUPTIBLE);
11084         }
11085 }